A phylogeny and classification of the Muhlenbergiinae (Poaceae: Chloridoideae: Cynodonteae) based on plastid and nuclear DNA sequences

Paul Peterson

Muhlenbergiaspatha, previously known only from near the type locality in San Luis Potosí, is reported from two localities in Zacatecas, Mexico. Historically, botanists have overlooked this diminutive annual. To clarify affinities of M.spatha, we present a molecular phylogeny emphasising species in M.subg.Pseudosporobolus using sequence data from two plastid markers (rpl32-trnL and rps16 intron) and nrDNA ITS. In addition, we include an updated description, illustration and discussion of the habitat of M.spatha.

A taxonomic treatment of 38 species of Muhlenbergia, a phylogeny based on analysis of six DNA sequence markers, and classification of Muhlenbergia for Central America (Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, Panama; and Campeche, Chiapas, Quintana Roo, Tabasco, and Yucatán, México) is given. With the support from a molecular phylogeny we describe Muhlenbergia subg. Ramulosaesubgen. nov. In our treatment we place M. gigantea (younger name) as a synonym of M. mutica. Lectotypes are designated for the names Agrostis microsperma Lag., Epicampes gigantea E. Fourn., Lamarckia tenella DC., Muhlenbergia adspersa Trin., M. diversiglumis Trin., M. exilis E. Fourn., M. flabellata Mez, M. setarioides E. Fourn., Pereilema ciliatum E. Fourn., P. crinitum var. cirratum E. Fourn., Podosemum ciliatum Kunth, P. tenuissimum J. Presl, and Schellingia tenera Steud.

A taxonomic treatment of the subtribe Muhlenbergiinae for northeastern Mexico (Coahuila, Nuevo Leon, and Tamaulipas) is given. A total of 39 native species are recognized in the study area in four genera: Aegopogon (1), Blepharoneuron (1), Lycurus (2), and Muhlenbergia (35). The names, Muhlenbergia glomerata var. ramosa Vasey and Muhlenbergia spiciformis Trim, are lectotypified. A key for determining the species, descriptions, distributions, specimens examined, illustrations, synonymies, and a brief discussion indicating relationships among all species of Muhlenbergia in northeastern Mexico are provided.

American Journal of Botany 97(9): 1532–1554. 2010. A PHYLOGENY AND CLASSIFICATION OF THE MUHLENBERGIINAE (POACEAE: CHLORIDOIDEAE: CYNODONTEAE) BASED ON PLASTID AND NUCLEAR DNA SEQUENCES1 Paul M. Peterson2,5, Konstantin Romaschenko2,3, and Gabriel Johnson4 2Smithsonian Institution, Department of Botany MRC-166, National Museum of Natural History, Washington, D.C. 20013-7012 USA; 3Laboratory of Molecular Systematics, Botanic Institute of Barcelona (CSIC−ICUB), Passeig del Migdia, s.n. 08038 Barcelona, Spain; and 4Department of Botany and Laboratories of Analytical Biology, Smithsonian Institution, Suitland, Maryland 20746 USA • Premise of the study: To understand the origins of C4 grasslands, we must have a better interpretation of plant traits via phylogenetic reconstruction. Muhlenbergiinae, the largest subtribe of C4 grasses in Mexico and the southwestern United States (with 176 species), is taxonomically poorly understood. • Methods: We conducted a phylogenetic analysis of 47 genera and 174 species using six plastid regions (ndhA intron, ndhF, rps16-trnK, rps16 intron, rps3, and rpl32-trnL) and the nuclear ITS 1 and 2 (ribosomal internal transcribed spacer) regions to infer evolutionary relationships and revise the classification. • Key results: In our analyses, Muhlenbergia (ca. 153 species) is paraphyletic, with nine genera (Aegopogon, Bealia, Blepharoneuron, Chaboissaea, Lycurus, Muhlenbergia, Pereilema, Redfieldia, Schaffnerella, and Schedonnardus) found nested within. We recognized the following five well-supported monophyletic lineages within Muhlenbergia: subg. Muhlenbergia, with species that have phosphoenolpyruvate carboxykinase-like leaf anatomy and long, scaly rhizomes; subg. Trichochloa with longlived species that are relatively tall (up to 3 m); subg. Clomena with 3-nerved upper glumes; sect. Pseudosporobolus species with narrow panicles and plumbeous spikelets; and sect. Bealia species with lemmas with hairy margins and midveins. • Conclusions: We propose expanding the circumscription of Muhlenbergia to include the other nine genera in this subtribe and make the following new combinations: Muhlenbergia subg. Bealia, M. diandra, M. geminiflora, M. paniculata, M. phleoides, M. subg. Pseudosporobolus (also lectotipified), M. solisii, M. tricholepis. We also propose several new names: M. ammophila, M. columbi, M. plumosa. Our phylograms suggest that Muhlenbergia originated in North America because the sister (Sohnsia filifolia and Scleropogoninae) is composed of predominantly North American species. Key words: biogeography; Chloridoideae; classification; ITS; Muhlenbergia; Muhlenbergiinae; phylogeny; plastid DNA sequences; Poaceae. Grassland ecosystems are one of the most easily recognized biomes in the world, covering about 40% of the earth’s surface (World Resources, 2000; Gibson, 2009), and they are also threatened and highly endangered. Humans evolved with grasslands, and we depend on grasses and grasslands for our sustenance directly as crops (rice, corn, and wheat) and indirectly as forage for herbivores. However, only a small fraction of grassland ecosystems remains intact today, and we need to study the biodiversity of this important biome from an evolutionary perspective before it is destroyed. The Muhlenbergiinae Pilg. is a diverse assemblage of C4 grasses containing 176 species that dominate grasslands in the western hemisphere. Species such as Muhlenbergia montana (Nutt.) Hitchc. (mountain muhly) and M. rigida (Kunth) Kunth 1 Manuscript received 19 November 2009: revision accepted 7 July 2010. The authors thank the National Geographic Society Committee for Research and Exploration, grant number 8087-06 for field support, the Smithsonian Institution’s Restricted Endowments Fund, National Museum of Natural History Small Grants Fund, the Scholarly Studies Program, Research Opportunities, Atherton Seidell Foundation, and Biodiversity Surveys and Inventories Program for financial support, J. H. Kirkbride, Jr. for translating German, A. Touwaide for correcting the Latin, and two anonymous reviewers for suggesting improvements. 5 Author for correspondence (e-mail: peterson@si.edu) doi:10.3732/ajb.0900359 (purple muhly) are the most common grass species of highplateau grasslands in north central Mexico, the southwestern United States, and, to a lesser extent, along the Andean Cordillera of South America. Yet evolutionary relationships and a modern classification of the Muhlenbergiinae based on the study of molecular characters have not been completed. To understand the origins and rise of C4 grasslands, a better interpretation of plant traits via phylogenetic reconstruction is essential (Edwards et al., 2010). The placement of Muhlenbergia Schreb. within the grasses has been the subject of many papers since the genus was included in the subfamily Festucoideae, tribe Agrostideae by Hitchcock (1935) [see Table 1 for a summary of taxonomic treatments in the Muhlenbergiinae]. The subtribe Muhlenbergiinae was first circumscribed by Pilger (1956) where he recognized a single genus, Muhlenbergia with the following eight sections: Acroxis (Trin.) Bush, Bealia (Scribn.) Pilg., Cinnastrum (E. Fourn.) Pilg., Clomena (P. Beauv.) Pilg., Muhlenbergia, Podosemum (Desv.) Pilg., Pseudosporobolus Parodi, and Stenocladium (Trin.) Bush. In this same treatment, Pilger recognized the genus Epicampes J. Presl (included in subtribe Sporobolinae Ohwi by Pilger), a name now placed in synonymy within Muhlenbergia. Subsequent authors have agreed that Pilger’s infrageneric treatment of Muhlenbergia was not phylogenetically informative (Soderstrom, 1967; Pohl, 1969; Morden, 1985; Peterson and Annable, 1991). With the accumulation of American Journal of Botany 97(9): 1532–1554, 2010; http://www.amjbot.org/ © 2010 Botanical Society of America 1532 September 2010] Peterson et al.—Phylogeny of Muhlenberginiinae Table 1. Primary taxonomic treatments found in the Muhlenbergiinae and the number of species in each taxon. Author Hitchcock, 1935 Pilger, 1956 Soderstrom, 1967 Pohl, 1969 Türpe 1973 J. Reeder, 1976 C. Reeder, 1985 Peterson, 1989b Peterson and Annable, 1990 Peterson and Annable, 1991 Peterson and Annable, 1992 Morden and Hatch, 1996 Herrera Arrieta, 1998 Peterson, 2000 Columbus et al., 2002 Taxa treated Muhlenbergia, USA and Mexico Muhlenbergiinae with 8 sections Muhlenbergia subg. Podosemum (=Trichochloa) sect. Epicampes Muhlenbergia subg. Muhlenbergia Aegopogon Redfieldia Lycurus Bealia Blepharoneuron “annual” species of Muhlenbergia Chaboissaea Muhlenbergia repens complex Muhlenbergia montana complex Muhlenbergiinae with 6 genera Schaffnerella No. of species 110 — 26 12 3 1 3 1 2 29 4 6 15 165 1 other types of data, i.e., leaf and embryo anatomy, Muhlenbergia became firmly placed in the Chloridoideae, although it has been aligned in a variety of tribes/subtribes, including Eragrostideae and Sporobolinae (Reeder, 1957; Stebbins and Crampton, 1961; Clayton and Renvoize, 1986; Peterson et al., 1995, 1997). Species within the Muhlenbergiinae are morphologically highly variable and can be characterized as having membranous ligules (rarely a line of hairs); paniculate inflorescences that are rebranched or composed only of primary branches; spikelets that are usually solitary but sometimes in pairs or triads, with cleistogenes (self-pollinated flowers that do not open at maturity) occasionally present in the leaf sheaths; one floret (rarely more) per spikelet that is perfect, staminate, or sterile; glumes that are awned or unawned; lemmas 3-nerved, awned or unawned; and a base chromosome number of x = 8−10 (Peterson et al., 1995, 1997, 2007a, b; Peterson, 2000). Two subtypes of C4 photosynthesis based on nicotinamide adenine dinucleotide cofactor malic enzyme (NAD-ME) and phosphoenolpyruvate carboxykinase (PCK) have been found in the Muhlenbergiinae with a few verified by biochemical assay (Gutierrez et al., 1974; Brown, 1977; Hattersley and Watson, 1992). On the basis of anatomy, morphology, and cytology, Soderstrom (1967) distinguished two subgenera within Muhlenbergia and divided M. subg. Podosemum (Desv.) Soderstr. (=M. subg. Trichochloa A. Gray, an older name) into two sections, sect. Podosemum (Desv.) Pilg. and sect. Epicampes (J. Presl) Soderstr. Two years later, Pohl (1969) completed a revision of 12 closely related species that he believed represented the entire M. subg. Muhlenbergia in North America. Based on anatomy, morphology, cytology, and flavonoid chemistry, 29 annual species of Muhlenbergia have been investigated and placed in tentative natural groups (Peterson and Rieseberg, 1987; Peterson, 1988a, b, 1989a; Peterson et al., 1989; Peterson and Annable, 1991). Morden and Hatch (1987, 1996) investigated the anatomical and morphological variation of six species they referred to as the M. repens complex. A biosystematics study investigating the M. montana complex (consisting of 15 species) has been completed (Herrera and Grant, 1993, 1994; Herrera Arrieta, 1998). Molecular genetic data of intersimple sequence repeats (ISSRs) were investigated for M. capillaris (Lam.) Trin., M. expansa (Poir.) Trin., and M. sericea (Michx.) P. M. Peterson (Gustafson and Peterson, 2007). 1533 The Muhlenbergiinae currently consists of 10 genera: Aegopogon (four spp. in North and South America; Türpe, 1973; Levin and Moran, 1989), Bealia (one sp., B. mexicana Scribn. in northern Mexico; Peterson, 1989b; Peterson et al., 1993), Blepharoneuron [two spp. in North America, B. shepherdii (Vasey) P. M. Peterson & Annable and B. tricholepis (Torr.) Nash, the latter an important range grass in the southwestern USA and northern Mexico; Peterson and Annable, 1990, 2003], Chaboissaea [four spp., three in central Mexico and C. atacamensis (Parodi) P. M. Peterson & Annable in Argentina and Bolivia; Peterson and Annable, 1992; Peterson and Herrera Arrieta, 1995; Sykes et al., 1997], Lycurus [three spp., including the amphitropical disjunct L. setosus (Nutt.) C. Reeder; Peterson and Morrone, 1998], Muhlenbergia [147 spp. centered in northern Mexico and the southwestern USA, containing the important range grass M. montana and the amphitropical disjuncts M. arenicola Buckley and M. torreyi (Kunth) Hitchc. ex Bush; Peterson and Ortíz Diaz, 1998; Peterson, 2003; Herrera Arrieta and Peterson, 2007; Peterson et al., 2007b; but also with seven species located in southeast Asia; Wu and Peterson, 2006]; Pereilema (four spp. in North, Central, and South America), Redfieldia [one sp., R. flexuosa (Thurb. ex A. Gray) Vasey in the southwestern USA, of probable hybrid origin; Reeder, 1976; Duvall et al., 1994], Schaffnerella [one sp., S. gracilis (Benth.) Nash in San Luis Potosí, Mexico; Columbus et al., 2002], and Schedonnardus [one sp., S. paniculatus (Nutt.) Trel., an amphitropical disjunct with spicate primary inflorescence branches]. Ninety-six percent of the species within the Muhlenbergiinae are native to the western hemisphere, and more than 80% of these are native to North America (Peterson et al., 2007a). Amphitropical disjuncts within the Muhlenbergiinae thus far tested have been shown to have North American origins (Peterson and Herrera Arrieta, 1995; Sykes et al., 1997; Peterson and Morrone, 1998; Peterson and Ortíz Diaz, 1998; Peterson et al., 2007a). Within Muhlenbergia, there are 127 species indigenous to North America (86%); 125 of these occur in Mexico (center of species diversity) and, of these, 56 are endemic (Peterson et al., 2007a). In preliminary molecular analyses, Muhlenbergia has appeared paraphyletic, with all nine remaining genera of Muhlenbergiinae nested within (Duvall et al., 1994; Hilu and Alice, 2001; Columbus et al., 2007, 2010; Peterson et al., 2010). Plastid restriction site markers supported the inclusion of Bealia Scribn., Blepharoneuron Nash, Chaboissaea E. Fourn., Lycurus, Pereilema J. Presl, and Redfieldia Vasey in the same subtribe as Muhlenbergia (Duvall et al., 1994). Columbus et al. (1998) found that Aegopogon Humb. & Bonpl. ex Willd. and Schaffnerella Nash, traditionally placed near Bouteloua Lag., actually were closely aligned with the large genus Muhlenbergia. What is quite unusual about these two genera is that they do not at first appear morphologically similar to Muhlenbergia. Aegopogon has spikelets in triads with the central sessile floret perfect and the two lateral pedicelled florets staminate or sterile. Muhlenbergia has only solitary spikelets. Hilu and Alice (2001) in their phylogeny of the Chloridoideae based on matK sequences included Schedonnardus Steud. in a well-supported clade with Aegopogon and Muhlenbergia. On the basis of anatomical characters, Muhlenbergia appears to be divisible into three major groups corresponding to two subgenera, Muhlenbergia subg. Muhlenbergia and M. subg. Trichochloa, the latter subgenus with two sections, Muhlenbergia sect. Epicampes and M. sect. Podosemum (Peterson 2000; Peterson and Herrera Arrieta, 2001). Analyzing ITS and trnL-trnF sequences of 52 species of American Journal of Botany 1534 Muhlenbergia, Columbus et al. (2010) also found support for two clades containing species of Muhlenbergia subg. Muhlenbergia and M. subg. Trichochloa. In a large molecular study of the entire Chloridoideae, Peterson et al. (2010) found strong support for the five clades within 33 sampled species of Muhlenbergiinae: Muhlenbergia subg. Muhlenbergia, M. subg. Trichochloa, M. sect. Bealia, M. subg. Clomena, and an unnamed clade that includes three species of Chaboissaea, two species of Lycurus, Redfieldia, Schaffnerella, Schedonnardus, M. arenacea (Buckley) Hitchc., M. richardsonis (Trin.) Rydb., and M. uniflora (Muhl.) Fernald. Using an analysis of plastid and nuclear DNA sequences, we provide a clear phylogeny for 124 of the 176 (70%) species that occur in the Muhlenbergiinae. We estimate the phylogeny of the Muhlenbergiinae based on the analysis of seven molecular markers (nuclear ITS and plastid ndhA intron, ndhF, rps16-trnK, rps16 intron, rps3, and rpl32-trnL DNA sequences). Previously, Columbus et al. (2010) considered 52 species of Muhlenbergia (plus 14 additional species from the other nine Muhlenbergiinae genera) for two molecular markers (nuclear ITS and plastid trnL-F DNA sequences). We include an expanded survey of the Muhlenbergiinae by sampling an additional 105 species for seven markers (687 new sequences), which is a significant advance over Peterson et al. (2010) and Columbus et al. (2010). Our study includes 109 species of Muhlenbergia, 15 additional species from the other nine Muhlenbergiinae genera and sequences for six plastid and ITS markers. We compare the ITS and plastid based phylogenies with the classifications in Columbus et al. (2010) and Peterson et al. (2001, 2007a, 2010). In addition, we seek morphological and anatomical characters supporting relationships in the molecular phylogenies and propose changes to the classification. [Vol. 97 sample from a different location for the same species. All vouchers are deposited in the Smithsonian Institution, United States National Herbarium (US). The majority of samples (89%) used in this study were collected by P. M. Peterson from 1984 to 2008. In addition, where feasible, we sampled older herbarium specimens to maximize the number of outgroup genera in the Chloridoideae. Molecular methods—All procedures where performed in the Laboratory of Analytical Biology (LAB) at the Smithsonian Institution. DNA was isolated using the BioSprint 96 DNA Plant Kit (Qiagen, Valencia, California, USA) following the protocol of the manufacturer. PCR amplifications were performed in MJ Research or PE 9700 thermal cyclers. Genomic DNA was combined with 1× reaction buffer (200 mM Tris-HCl, 500 mM NH4) [Bioline Biolase Taunton, Madison, Wisconsin, USA] without Mg2+, 2 mM MgCl2, 200 mM dNTPs, 1.5 µL of Taq polymerase (Bioline Biolase Taunton), 40 pmol/µL each of forward and reverse primers. We targeted seven regions for sequencing: three from the plastid large single copy (LSC) region: rps3 (coding), rps16 intron, and 3′rps16-5′trnK (spacer); three from the small single copy (SSC) region: ndhF (coding), ndhA intron, and rpl32trnL (spacer); and nrDNA ITS. Intergenic spacers rpl32-trnL (SSC) and rps16trnK (LSC) are two of the top ranked, most variable noncoding regions for phylogenetic studies in the angiosperms (Shaw et al., 2007). We chose the widely used ndhF gene (SSC) to recover phylogenetic relationships because it proved useful in other groups of grasses (Giussani et al., 2001; Soreng et al., 2007; Romaschenko et al., 2010). The sequences, melting temperature, quality, and references for the primers used are given in Peterson et al. (2010). The amplification parameters for all plastid and the nuclear ribosome ITS regions follow Peterson et al. (2010). All PCR products were cleaned with ExoSAP-IT (USB, Cleveland, Ohio, USA). DNA sequencing was performed with BigDye Terminator Cycle Sequencing v.3.1 (PE Applied Biosystems, Foster City, California, USA) according to the following parameters: 80°C, 5 min; 25 or 30 cycles of 95°C for 10 s, 50°C for 5 s and 60°C for 4 min. Sequenced products were analyzed on an ABI PRISM 3730 DNA Analyzer 7900HT. The regions rpl32-trnL, rps3, rps16 intron, 3′rps16-5′trnK, ndhF (coding region), and ITS were sequenced in one direction. Relatively short regions (500–750 bp) covered by our primers were easily interpreted allowing us to accumulate sequences from different parts of the genome for phylogenetic inference (Shaw et al., 2005, 2007). The ndhA intron (933 bp) was sequenced in both directions and the program Sequencher 4.8 (Gene Code Corp., Ann Arbor, Michigan, USA, 1991–2007) was employed to produce the contig sequence for the entire region. MATERIALS AND METHODS Taxon sampling—Representatives of 37 genera were chosen as outgroups from the Chloridoideae clade in Peterson et al. (2010): Aeluropus, Allolepis, Astrebla, Austrochloris, Blepharidachne, Bouteloua, Chloris, Crypsis, Cynodon, Dasyochloa, Distichlis, Eleusine, Erioneuron, Gouinia, Gymnopogon, Hilaria, Jouvea, Lepturus, Microchloa, Monanthochloe, Monelytrum, Mosdenia, Munroa, Orinus, Perotis, Pogonarthria, Scleropogon, Sohnsia, Sporobolus, Swallenia, Tragus, Trichoneura, Tridens, Trioidia, Vaseyochloa, Willkommia, and Zoysia (for a complete list of species see Appendix 1). Voucher information and GenBank numbers for 178 accessions representing 162 species are given in Appendix 1. Fifteen of the accessions included a second Table 2. Phylogenetic analyses—Sequence alignment was done manually using the program BioEdit v.7.0.5.3 (Hall, 1999). Several ambiguously aligned regions were excluded from analyses. The length of sequences and amount of excluded data for each region is presented in Table 2. We used the maximum parsimony analysis implemented in PAUP* to calculate the tree length (TL), consistency index (CI), homoplasy index (HI), retention index (RI), and rescaled consistency index (RC) for separate and combined regions (Table 2). No data were excluded from rps3, rps16 intron, and ndhA intron. All gaps were treated as missing data. We used maximum likelihood and Bayesian analysis to infer phylogeny. The maximum likelihood (ML) analysis was conducted with the program GARLI 0.951 (Zwickl, 2006). Bayesian and maximum likelihood analyses yielded trees Summary data for six plastid regions and nrDNA ITS used in this study. Characteristic ndhF rpl32-trnL rps16-trnK rps3 rps16 intron ndhA intron Plastid ITS Aligned sequence length Average sequence length No. of taxa No. of excluded characters Proportion of excluded characters (%) No. of PIC PIC/SL Tree length Consistency index Homoplasy index Retention index Rescaled consistency index Akaike information criterion 796 734 163 2 0.3 169 0.230 569 0.4271 0.5729 0.8344 0.3564 GTR+G 1389 695 175 364 26.2 258 0.371 761 0.5361 0.4639 0.8450 0.4530 TVM+G 1222 723 174 213 17.4 221 0.306 575 0.5513 0.4487 0.8428 0.4646 TVMef+G 590 579 174 0 0.0 85 0.147 254 0.4764 0.5236 0.8679 0.4135 TVM+G 1368 745 165 0 0.0 159 0.213 400 0.5800 0.4200 0.8768 0.5086 K81uf+G 1424 933 161 0 0.0 256 0.274 708 0.5508 0.4492 0.8674 0.4778 K81uf 6789 4409 177 579 8.5 1148 0.260 3369 0.508 0.492 0.844 0.429 GTR+G 814 669 172 89 10.9 312 0.466 2373 0.284 0.716 0.689 0.196 GTR+G Notes: PIC, parsimony informative characters; SL = sequence length Combined plastid+ITS 7603 5078 179 743 9.8 1460 0.288 5859 0.407 0.593 0.784 0.319 GTR+G September 2010] Peterson et al.—Phylogeny of Muhlenberginiinae with visually similar topology, i.e., the trees are visually the same, but some branch lengths could differ minutely. A test run of Bayesian analysis for the combined data sets under the single GTR+G model yielded the same topology and posterior probability (PP) values as the Bayesian analysis for a partitioned data set performed under models suggested by MODELTEST for separate regions. The Akaike information criterion (AIC) scores are indicated in Table 2 (Kimura, 1981; Tavaré, 1986; Posada and Crandall, 1998). Very little conflict was observed among maximum likelihood trees in the individual plastid analyses. The incongruence length difference (ILD) test (Farris et al., 1994) was implemented in the program WinClada ver. 1.00.08 (Nixon, 2002) to test for incongruence between the ITS and plastid data sets. Default parameters for 1000 replicates were executed. Bootstrap analyses (Felsenstein, 1985) were performed for the ML analysis using GARLI with the default parameters for 1000 replicates, with the program PAUP* ver. 4.0b10 (Swofford, 2000) used to compute the bootstrap consensus tree. Bootstrap (BS) values of 90–100% were interpreted as strong support, 70–89% as moderate, and 50–69% as weak. Bayesian posterior probabilities were estimated using the program MRBAYES ver. 3.01 (Huelsenbeck and Ronquist, 2001; Ronquist et al., 2005) with DNA substitution models selected using the program MrModeltest ver. 1.1b (Nylander, 2002). The plastid data set and combined plastid+ITS data set for Bayesian analysis were then partitioned into two subsets that were processed implementing different parameters suggested by MrModeltest concerning the model for among site rate variation, number of substitution types, substitution rates, and gamma shape parameter. All other parameters were left at default settings. Each Bayesian analysis was initiated with random starting trees and was initially run for 2 million generations, sampling once per 100 generations. The analysis was continued until the value of standard deviation of split sequences dropped below 0.01 as the convergence diagnostic value (Huelsenbeck and Ronquist, 2001). The fraction of the sampled values discarded as burn in was set at 0.25. RESULTS Phylogenetic analyses— A total of 687 sequences representing 105 species are newly reported in GenBank (Appendix 1). Lengths sequenced for individual regions are noted in Table 2. Plastid rpl32-trnL had the highest rate of amplification and successful sequencing with 99% of taxa recovered across the entire data set. Recovery in other plastid regions ranged from 91–98%, and the effectiveness of sequencing the ITS region was 97% (Table 2). An average of 4.5% of data was missing across the entire data set. As expected, ITS provided the most information per aligned nucleotide (Table 2; the ratio of the number of parsimony informative characters (PIC) per sequence length (SL) was 0.466, compared with 0.147–0.371 for plastid regions). Analysis of ITS sequences— There are five major clades within a monophyletic Muhlenbergiinae (moderate support), labeled in Fig. 1 as Muhlenbergia sect. Bealia (strong support), M. subg. Trichochloa (strong support), M. subg. Clomena (moderate support), M. sect. Pseudosporobolus (weak support), and M. subg. Muhlenbergia (moderate support). Muhlenbergia sect. Bealia and subg. Trichochloa share a common ancestor (strong support), and M. subg. Clomena and sect. Pseudosporobolus form a clade (moderate support) that is sister to M. subg. Muhlenbergia (strong support). Muhlenbergia ramulosa is sister to the rest of the Muhlenbergiinae. Muhlenbergia sect. Bealia consists of 20 taxa and contains strongly supported clades of M. caxamarcensis and M. filiformis; two accessions of Blepharoneuron shepherdii; M. argentea, M. eludens, and M. flavida; M. arenicola and M. torreyi, which are sister to eight annual species; and M. minutissima and M. sinuosa. There are 42 taxa included within M. subg. Trichochloa clade (six of these have two samples per species) and these show very little sequence divergence because all branches are very short. A single clade exhibits strong support for two acces- 1535 sions of M. lucida. Muhlenbergia subg. Clomena contains 11 taxa (two of these have two samples per species) divided into two well-supported clades: M. durangensis-M. flaviseta sister to the remaining species. Muhlenbergia sect. Pseudosporobolus consists of 22 taxa (three of these have two samples per species) and contains strongly supported clades comprising M. implicata and M. jaime-hintoni; two different accessions of M. uniflora; M. fastigiata sister to two accessions of M. richardsonis; two different accessions of Lycurus setosus; and Chaboissaea subbiflora, C. atacamensis, and C. ligulata. There are 38 taxa within M. subg. Muhlenbergia (two of these have two samples per species) with seven well-supported clades: M. spiciformis and M. tenuifolia; M. appressa, M. brandegei, and M. microsperma; Pereilema beyrichianum and P. crinitum; M. ciliata, M. pectinata, and M. tenella; Aegopogon cenchroides and A. tenellus; M. andina, M. curtifolia, and M. thurberi; and M. sobolifera and M. tenuiflora. Analysis of plastid sequences— As in the ITS tree, five major clades appear to be within a monophyletic Muhlenbergiinae (strongly supported), and these are labeled in Fig. 2 as Muhlenbergia sect. Bealia (weakly supported), M. subg. Trichochloa (moderately supported), M. subg. Clomena (moderately supported), M. sect. Pseudosporobolus (weakly supported), and M. subg. Muhlenbergia (strongly supported). Species composition in each of these five clades is identical with the ITS-derived phylogram, except for the five additional taxa included in the data set. As in the ITS-derived phylogram, Muhlenbergia sect. Bealia and subg. Trichochloa share a common ancestor (strongly supported), and M. subg. Clomena and sect. Pseudosporobolus form a clade (moderately supported) that is sister to M. subg. Muhlenbergia (moderately supported. Muhlenbergia ramulosa is sister to M. sect. Bealia and M. subg. Trichochloa (strongly supported). There is considerably higher backbone support among clades within Muhlenbergia sect. Bealia, and there is one additional taxon not included in the ITS data set, M. vaginata, that forms a clade with M. filiformis (strongly supported); sister to this is M. caxamarcenis (strongly supported). Other strongly supported clades in M. sect. Bealia include M. arizonica-M. argenteaM. eludens-M. flavida, two species of Blepharoneuron with two accessions of B. shepherdii, and two clades that are sister: ((M. minutissima, M. texana)(M. sinuosa (M. brevis, M. depauperata))) and ((M. arenicola, M. torreyi)(M. fragilis (M. annua, M. majalcensis))). Muhlenbergia subg. Trichochloa contains more internal support as compared to the ITS-derived phylogeny with strong support for separate clades containing M. elongata, M. emersleyi, and M. lucida; and M. involuta, M. reverchonii, and M. sericea. The two accessions each of M. dubia, M. lucida, M. pubescens, and M. rigida do not form sister groups. In the M. subg. Clomena clade, Muhlenbergia filiculmis, M. jonesii, two accessions of M. montana and M. virescens, M. quadridentata and M. straminea form a well-supported clade; sister to this are M. crispiseta-M. peruviana pair (strongly supported). As in the ITS-derived phylogeny, M. durangensis-M. flavida pair (strongly supported) is sister to the remaining species in M. subg. Clomena. Backbone support for M. sect. Pseudosporobolus is much higher in the plastid-derived phylogram, and the topology is somewhat different than in the ITS tree. Strongly supported clades include two accessions of Lycurus setosus, M. palmirensis-M. villiflora var. villosa, Chaboissaea subbiflora sister 1536 American Journal of Botany [Vol. 97 Fig. 1. Phylogram of best maximum likelihood tree from analysis of nuclear ITS data. Numbers above branches represent bootstrap values; numbers below branches are posterior probability values. (A) Detail of upper portion and (B) lower portion of phylogram. Abbreviations for subtribes: A = Aeluropodinae, B = Boutelouinae, E = Eleusininae, H = Hilariinae, Mo = Monanthochloinae, Sc = Scleropogoninae, Td = Triodinae, Tg = Traginae, Tt = Tridentinae. Taxon color indicates native distribution: green = North America, blue = South America, purple = North and South America, red = southeast Asia. September 2010] Peterson et al.—Phylogeny of Muhlenberginiinae 1537 1538 American Journal of Botany to C. atacamensis-C. ligulata, Redfieldia flexuosa sister to two accessions of M. uniflora, M. fastigiata sister to M. repens-M. utilis with these three sister to two accessions of M. richardsonis. One other large clade with strong support includes Schedonnardus paniculatus as sister to a clade of (in phylogenetic order) three species of Chaboissaea, M. cuspidata, M. palmirensis-M. villiflora var. villosa, M. wrightii, Schaffnerella gracilis, and two accessions of Lycurus setosus. Muhlenbergia jaime-hintoni is sister to Redfieldia flexuosa-M. uniflora (Fig. 2B) rather than to M. implicata in the ITS tree (Fig. 1B). The topology of the plastid-derived phylogram for M. subg. Muhlenbergia is similar to that portrayed by the ITS-derived phylogram, although many branches have higher support values and the topology of a few clades is different. A derived, moderately supported clade with all species occurring in southeast Asia includes M. ramosa sister (strongly supported) to two accessions of M. japonica (moderately supported) and M. himalayensis-M. huegelii (strongly supported). Other strongly supported clades includeM. racemosa-M. tenuiflora (in the ITS tree, M. tenuiflora forms a strongly supported clade with M. sobolifera), M. andina sister to M. curtifolia-M. thurberi, M. pauciflora and M. glauca 21023 (there are two different accessions for this species, see Appendix 1) -M. polycaulis, Pereilema beyrichianum-P. crinitum, M. breviseta-M. dumosa, M. alamosae sister to M. tarahumara that is sister to Aegopogon cenchroides-A. tenellus, M. arsenei (in the ITS tree, M. arsenei is sister to Pereilema crinitum-P. beyrichianum) sister to M. tenella -M. ciliata-M. pectinata, M. spiciformis-M. tenuifolia sister to M. porteri that is sister to M. appressa-M. brandegei-M. microsperma. Muhlenbergia mexicana var. filiformis is a moderately supported sister to clade (M. sobolifera (M. californica (M. racemosa, M. tenuiflora))), whereas in the ITS tree it is sister to M. californica in a larger clade, ((M. sobolifera, M. tenuiflora)(M. racemosa (M. californica, M. mexicana var. filiformis))). Analysis of combined plastid and ITS sequences— The ILD test (P = 0.1667; 99% confidence level) failed to reject the null hypothesis of congruence between the ITS and plastid data sets; therefore, we combined them. As in the ITS and combined plastid trees, five major clades seem to be within a monophyletic Muhlenbergiinae (strongly supported), and these are labeled in Fig. 3 as Muhlenbergia sect. Bealia (strongly supported), M. subg. Trichochloa (strongly supported), M. subg. Clomena (moderately supported), M. sect. Pseudosporobolus (moderately supported), and M. subg. Muhlenbergia (strongly supported). Species composition in each of these five clades is again identical with the ITS and plastid-derived phylograms. As in the other analyses, Muhlenbergia sect. Bealia and subg. Trichochloa share a common ancestor (strongly supported), and M. subg. Clomena and sect. Pseudosporobolus form a clade (strongly supported) that is sister to M. subg. Muhlenbergia (strongly supported). Muhlenbergia ramulosa is sister to M. sect. Bealia and M. subg. Trichochloa as in the ITS-derived phylogram. The overall topology of the combined phylogram is remarkably similar to that of the plastid-derived tree, even in the terminal branches. There are only some minor differences with the plastid phylogeny, most notably in M. sect. Pseudosporobolus where M. fastigiata is sister (strongly supported) to two accessions of M. richardsonis and in M. subg. Muhlenbergia where M. sobolifera-M. tenuiflora form a clade (strongly supported) that is sister (strongly supported) to M. racemosa, M. californica, [Vol. 97 and M. mexicana var. filiformis. However, these relationships were depicted in the ITS-derived phylogram. Therefore, in the following sections we will refer to the combined plastid ITSderived phylogram when discussing evolutionary scenarios. In the discussion section, we make all necessary combinations and new names within Muhlenbergia. Analysis of outgroups— Determination of the sister to the Muhlenbergiinae allows us to test the monophyly of the subtribe and to polarize morphological and anatomical characters. The ITS and plastid trees differed in relative branch length, support values that occur on these branches, and topology among the 38 taxa used as outgroups. In the ITS phylogram (Fig. 1) the sister to the Muhlenbergiinae was a clade (PP = 0.75) containing Sohnsis filifolia as sister to the Scleropogoninae. In the plastid and combined ITS/plastid tree (Figs. 2, 3), Sohnsia filifolia was sister to the Muhlenbergiinae, and the Scleropogoninae was the sister group to both of these. Relative positions of Swallenia, Tragus, and Jouvea differ among the ITS, plastid, and combined ITS/plastid phylograms. Relationships among these three taxa in the tribe Cynodonteae have been thoroughly investigated by Peterson et al. (2010) using a much broader sample. DISCUSSION Monophyly of the Muhlenbergiinae is moderately to strongly supported by our data in all trees and Muhlenbergia, as traditionally treated by agrostologists, is depicted as paraphyletic with Aegopogon, Bealia, Blepharoneuron, Chaboissaea, Lycurus, Pereilema, Redfieldia, Schaffnerella, and Schedonnardus embedded within this clade (Duvall et al., 1994; Hilu and Alice, 2001; Columbus et al., 2007, 2010; Peterson et al., 2010). Because the monophyly of Muhlenbergia s.s. or s.l. is not supported by phylogenetic analysis of ITS, matK, ndhA intron, ndhF, rps16-trnK, rps16 intron, rps3, and rpl32-trnL, trnL-trnF sequences, and RFLP studies (Duvall et al., 1994; Hilu and Alice, 2001; Columbus et al., 2007, 2010; Peterson et al., 2010), we are incorporating all nine genera within Muhlenbergia. Within the Muhlenbergia clade (=Muhlenbergiinae) there are five large, well-supported clades: Muhlenbergia sect. Bealia, M. subg. Trichochloa, M. subg. Clomena, M. sect. Pseudosporobolus, and M. subg. Muhlenbergia. The M. subg. Muhlenbergia clade includes only species that exhibit PCK-like leaf anatomical characteristics, where the chlorenchyma is composed of tabular cells that are indistinctly radiate and continuous between bundles [PCK type, defined as centrifugal/evenly distributed photosynthetic carbon reduction (PCRD) cell chloroplasts (with grana), the major veins (which, at maturity have a protoxylem lacuna and large metaxylem elements) are surrounded by two bundle sheaths, an inner mestome sheath of elongate nonchlorenchymatous cells and an outer chlorenchymatous sheath of shorter PCRD cells (designated XyMS+structural type; Hattersley and Watson, 1976, 1992; Dengler et al., 1986) with suberized lamella, fan- to shield-shaped bulliform cells without formation of a complete column of colorless cells from the adaxial to the abaxial surface, and species that have four or more secondary and/or tertiary vascular bundles between consecutive primary vascular bundles (Peterson and Herrera Arrieta, 2001). Morphologically, members of the M. subg. Muhlenbergia clade have broad, flat leaf blades, most have well-developed, scaly, and creeping rhizomes, and panicles that are usually narrow at maturity September 2010] Peterson et al.—Phylogeny of Muhlenberginiinae (M. porteri is an exception with open, 6–15 cm wide panicles) (Peterson, 2003). Our study supports a previous hypothesis of Peterson and Herrera Arrieta (2001) that within Muhlenbergia the evolution of the PCK subtype of photosynthesis was a single evolutionary event. Early in the evolution of Muhlenbergia, the PCK-like condition appears to have arisen once, because all species that have been chemically assayed as PCK occur in this clade (Gutierrez et al., 1974; Brown, 1977). Ecologically, Muhlenbergia PCK-like species are able to flourish in shaded sites and forest margins with low-light intensities and moisthumid microhabitats that are not normally occupied by their NAD-ME relatives. In our ITS phylogram within the M. subg. Muhlenbergia clade, species of Pereilema do not appear monophyletic because they form a poorly supported grade (BS = 67, PP = 0.97), and P. ciliatum is paired with M. flexuosa (unsupported). In our plastid and combined phylogram, all species of Pereilema form a weak to moderately supported clade. Because it would require quite a few parallel evolutionary events to select for the morphological features expressed in this genus, our plastid markers may be a better estimate of phylogeny in this lineage. All four species of Pereilema have two unique characters: sterile, bristle-like spikelets that subtend the fertile spikelets and prominent blade auricles that are usually ciliate (Peterson, 2000). Embedded with M. subg. Muhlenbergia is a strongly supported clade containing Aegopogon cenchroides and A. tenellus. The four species of Aegopogon have a false spike with each branch usually bearing three spikelets with one larger spikelet perfect and the other two smaller and often staminate or rudimentary (two spikelets in A. bryophilus Döll with one spikelet often not developed) (Peterson, 2000). The recently described species M. tarahumara (Peterson and Columbus, 2009) was found in our study to be sister to Aegopogon in all trees. Muhlenbergia tarahumara differs from other species of Aegopogon by having panicle branches with only two terminal, perfect spikelets (Peterson and Columbus, 2009). Anatomically, M. tarahumara also differs from other species in M. subg. Muhlenbergia by having noncontiguous chlorenchyma separated by columns of colorless cells between adjacent vascular bundles. Other species in this clade (M. pauciflora and M. polycaulis) exhibit this leaf anatomical characteristic, at least near the middle of the blades. However, near the leaf margins, the tertiary vascular bundles of these latter two species have chlorenchyma tissue that is continuous between each adjacent vascular bundle. All other characteristics, i.e., presence of two bundle sheaths, uneven outline of the outer sheath, round shape of chloroplasts in the outer sheath, and centrifugal/peripheral position of the chloroplasts in each cell, are predictive of PCK for M. pauciflora, M. polycaulis, and M. tarahumara. Because the habitat where M. tarahumara is found is rather xeric (slopes, ridge tops, rock outcrops), the columns of colorless cells between adjacent vascular bundles, like most NAD-ME species, facilitate involution of the leaf blades, an adaption to periods of drought. PCK-like leaf anatomy appears to have arisen once in the evolution of the Muhlenbergiinae, and this morphology is linked to species that occupy slightly more mesic habitats (Peterson and Herrera Arrieta, 2001). The anatomical structure found in M. tarahumara, and to some extent in M. pauciflora and M. polycaulis, might be in direct response to the environment where reversion to NAD-MElike leaf structure is likely an adaptive feature. The Chinese species M. himalayensis, M. hueglii, M. japonica, and M. ramosa form a clade within M. subg. Muhlenbergia with moderate bootstrap support in the plastid and combined 1539 plastid/ITS phylograms, suggesting a single colonization event, most likely from North American origins. Only seven native species of Muhlenbergia occur in southeast Asia, and all seven are reported in the flora of China (Wu and Peterson, 2006). The Asian species of Muhlenbergia are predominately rhizomatous (only M. duthieana Hack. is loosely caespitose without rhizomes) and occur in similar habitats to most species in M. subg. Muhlenbergia, such as mountain slopes, forests, and along moist roadsides. Muhlenbergia californica, M. mexicana var. filiformis, M. racemosa, M. schreberi, M. sobolifera, and M. tenuiflora are sister to these Chinese species, and together they are sister to the remaining species within M. subg. Muhlenbergia, suggesting that colonization from North America to southeastern Asia occurred relatively recently in the evolution of this subgenus (Figs. 1–3). Three sections of Muhlenbergia recognized by Pilger (1956): sect. Acroxis (M. dumosa, M. mexicana, M. polycaulis, and M. racemosa), sect. Muhlenbergia (M. schreberi), and sect. Stenocladium (M. bushii R. W. Pohl, M. hueglii, M. japonica, M. ramosa, M. sobolifera, and M. tenuiflora) included species in our subg. Muhlenbergia clade. In our phylograms, there are no clades that correspond with Pilger’s sections; therefore, we agree with earlier authors that his treatment was not phylogenetically informative (Soderstrom, 1967; Pohl, 1969; Morden, 1985; Peterson and Annable, 1991). Although the clade of species representing the M. subg. Trichochloa is strongly supported in our analyses (Figs. 1, 3), there is little resolution among members, likely reflecting very low levels of divergence within our plastid and nrDNA ITS sequences. The low level of divergence may be a consequence of rapid speciation events. It is possible that some species delimitations of subg. Trichochloa are not tenable because of recent diversification although it may also be the case that suitable molecular markers have yet to be applied. Within Muhlenbergia, this group is by far the most difficult to determine because there are very few morphological differences among the taxa and discrete (nonplastic) characteristics are few. Anatomically, most species in this clade have sclerosed phloem, a crown of inflated cells located adaxially to the primary vascular bundles, unequal secondary and tertiary vascular bundles, and primary vascular bundles that are either rectangular or obovate/elliptic in shape (Peterson and Herrera Arrieta, 2001). Species in M. subg. Trichochloa are erect, relatively tall (0.8–3 m), robust and stout, caespitose perennials that have unnerved or 1-nerved glumes (Soderstrom, 1967; Peterson, 2000). Pilger (1956) recognized M. sect. Cinnastrum with narrowly contracted, spicate panicles (M. angustata, M. macroura, and M. rigens) and M. sect. Podosemum with open panicles, lemmas long aristate, new shoots inside the sheaths (intravaginal), and ligule extended (M. articulata, M. capillaris, M. distichophylla, M. longiglumis, M. rigida, and M. stricta). Pilger’s two sections do not include the same species as M. subg. Trichochloa sects. Epicampes and Podosemum as described in Peterson and Herrera Arrieta (2001), but the species treated by Soderstrom (1967) in his subg. Podosemum (=M. subg. Trichochloa) are the same. The clade of M. subg. Clomena (=M. montana complex sensu Herrera Arrieta, 1998) is moderately supported in our analysis, and morphologically, this complex includes species that have 3-nerved upper glumes that are often 3-toothed and densely caespitose individuals with lower leaf sheaths that become flat and somewhat papery at maturity (Reeder and Reeder, 1995; Herrera Arrieta, 1998). Muhlenbergia argentea, a species with 1-nerved upper glumes, slightly compressed-keeled sheaths, 1540 American Journal of Botany [Vol. 97 Fig. 2. Phylogram of best maximum likelihood tree from analysis of plastid data. Numbers above branches represent bootstrap values; numbers below branches are posterior probability values. (A) Detail of upper portion and (B) lower portion of phylogram. Abbreviations for subtribes: A = Aeluropodinae, B = Boutelouinae, E = Eleusininae, H = Hilariinae, Mo = Monanthochloinae, Sc = Scleropogoninae, Td = Triodinae, Tg = Traginae, Tt = Tridentinae. Taxon color indicates native distribution: green = North America, blue = South America, purple = North and South America, red = southeast Asia. September 2010] Peterson et al.—Phylogeny of Muhlenberginiinae 1541 1542 American Journal of Botany and flattened caryopses (Reeder and Reeder, 1995) was included by Herrera Arrieta (1998) in her study of the M. montana complex; however, this taxon occurs in our clade of M. subg. Bealia. We provide evidence for the exclusion of M. argentea and the addition of two annual species, M. crispiseta and M. peruviana (Peterson and Annable, 1991) to be included in M. subg. Clomena. Within our clade of M. subg. Clomena, there are three strongly supported subclades, one that includes the two annual species, a second that includes M. durangensis and M. flaviseta, and a third that includes those species with morphologies very similar to M. montana. Some individuals of M. montana and M. virescens have sclerosed phloem. This characteristic apparently has arisen four times within Muhlenbergia because it also is found in subg. Trichochloa, in M. arenicola and M. torreyi (subg. Bealia), and in M. jaime-hintoni (sect. Pseudosporobolus) (Peterson and Herrera Arrieta, 2001). The moderately supported clade of M. sect. Pseudosporobolus (Fig. 3) includes a diverse assemblage of species, such as Schedonnardus paniculatus, that has panicles with long primary branches that do not rebranch, hence containing nearly sessile spikelets; Redfieldia flexuosa with 2–6-flowered spikelets, a line of hairs for a ligule, and open and diffuse panicles with capillary branches very similar to M. asperifolia, also occasionally with 2- or 3-flowered spikelets; Schaffnerella gracilis, a little known endemic of San Luis Potosí, Mexico (Columbus et al., 2002) that has panicles composed of short primary branches, each bearing a triad of 1-flowered spikelets, 7–9-nerved lemmas that have 3–5 awns, all enclosed in a spathiform sheath; Lycurus setosus with spikelets that are grouped in pairs, one sessile and one pedicellate; and Chaboissaea with one or two (occasionally three) florets per spikelet, the lower floret perfect and the upper florets staminate or sterile (Reeder, 1985; Sánchez and Rúgolo de Agrasar, 1986; Peterson and Annable, 1992; Peterson 2000; Peterson et al., 2007b). Embedded in M. sect. Pseudosporobolus is a strongly supported clade (Fig. 3) consisting of M. fastigiata, M. repens, M. richardsonis, and M. utilis, all earlier treated as the M. repens complex (Morden, 1985; Morden and Hatch, 1987, 1996). These four species are characterized by having short culms seldom exceeding 40 cm in height; a rhizomatous perennial habit, short involute leaf blades; short, narrow, contracted panicles; plumbeous spikelets; and unawned or mucronate lemmas (Morden, 1985; Morden and Hatch, 1987, 1996). Muhlenbergia villiflora var. villosa was included in Morden’s M. repens complex, but in our analyses, it is sister to the Ecuadorian endemic M. palmirensis (Fig. 3, moderately supported; Fig. 2, strongly supported). Most species in M. sect. Pseudosporobolus have well-developed abaxial and adaxial sclerenchyma in their primary vascular bundles, narrow panicles, usually plumbeous spikelets, and unawned to mucronate lemmas (Peterson and Herrera Arrieta, 2001). Exceptions to these general trends include the short-awned Lycurus setosus and long-awned M. implicata, and the broad and open-panicled M. asperifolia, M. implicata, and Redfieldia flexuosa. The characteristic of having 2–3(–6)-flowered spikelets is also quite common in M. sect. Pseudosporobolus because it is found in Chaboissaea atacamensis, C. ligulata, C. subbiflora, M. arenacea, M. asperifolia, M. cuspidata, M. fastigiata, M. richardsonis, M. uniflora, and Redfieldia flexuosa. The strongly supported clade of M. sect. Bealia contains few unique morphological characteristics shared among its members. However, all species in this clade have lemmas with hairy margins and midveins and caespitose or tufted culms, characters that are shared by many species in the M. subg. Trichochloa [Vol. 97 and subg. Clomena. Of the 20 species in M. sect Bealia, 14 are annual, with only Blepharoneuron tricholepis, M. arenicola, M. argentea, M. arizonica, M. caxamarcensis, and M. torreyi being perennial. Blepharoneuron was originally erected by Nash (1898) to emphasize the densely pilose margins and midvein of the lemma found in B. tricholepis. Blepharoneuron shepherdii also has densely pilose margins and midvein of the lemma and a base chromosome number of x = 8, prompting Peterson and Annable (1990) to place Muhlenbergia shepherdii (Vasey) Swallen in Blepharoneuron. The overall morphology of B. shepherdii with species in the M. fragilis-M. annuaM. majalcensis clade (Fig. 3, moderately supported) and the M. minutissima-M. sinuosa pair (Fig. 3, moderately supported) is striking because all are slender annuals with unawned lemmas, with capillary, flexuous pedicels that are often nodding (Peterson and Annable, 1990, 1991). Sister to the Blepharoneuron pair is a strongly supported clade comprising M. caxamarcensis, M. filiformis, and M. vaginata (Fig. 3). With the inclusion of M. ligularis (Columbus et al., 2010), these latter four taxa form a tight assemblage of short-lived perennial to annual, mat-forming species with short culms not exceeding 35 cm in height, narrow to loosely contracted panicles, and unawned, mucronate or shortawned lemmas (Laegaard and Sánchez Vega, 1990; Peterson and Annable, 1991). Morphologically, these four species closely resemble the M. repens complex (M. sect. Pseudosporobolus) as previously discussed, but differ primarily by lacking welldeveloped rhizomes, a characteristic common in M. subg. Muhlenbergia and M. arenacea, M. asperifolia, M. jaime-hintonii, M. palmirensis, M. villiflora var. villosa, and Redfieldia flexuosa, all members of M. sect. Pseudosporobolus. In our study, M. ramulosa does not align within any subgenus or section but is sister to all Muhlenbergiinae in the ITS phylogram (not well supported in Fig. 1) or sister to M. sect. Bealia and M. subg. Trichochloa in the plastid and combined phylograms (strongly supported in Figs. 2 and 3). Earlier molecular studies of the Muhlenbergiinae (ITS and trnL-F) are also unable to confirm the affinity of M. ramulosa (Columbus et al., 2010), clearly a distinctive taxon, phylogenetically, wherever it belongs. Morphologically, M. ramulosa is very similar to many of the small delicate annuals that reside in M. sect. Bealia. At this time, we are not prepared to erect a subgeneric ranking to accommodate only M. ramulosa. Cleistogamous spikelets appear to have evolved twice within the Muhlenbergiinae, once in the M. subg. Muhlenbergia where M. appressa, M. brandegei, and M. microsperma (all annuals) form a strongly supported clade (Fig. 3) and in M. sect. Pseudosporobolus known only from a few collections of M. cuspidata (Morden and Hatch, 1984). The formation of cleistogamous spikelets could actually be more common among the Muhlenbergiinae, but is undocumented to date. Sclerosed phloem appears to have evolved a minimum of four times within the Muhlenbergiinae because it is found in M. arenicola-M. torreyi clade in sect. Bealia, the subg. Trichochloa clade, the subg. Clomena clade, and in M. jaime-hintonii (sect. Pseudosporobolus). In a cladogram derived entirely on the analysis of 16 anatomical characters within Muhlenbergia, Peterson and Herrera-Arrieta (2001) indicated that sclerosed phloem originated twice. Biogeography— All three phylograms suggest that the Muhlenbergiinae originated in North America; for example, the sister group (Scleropogoninae in Fig. 1; or Sohnsia filifolia and Scleropogoninae in Figs. 2 and 3) are predominantly North September 2010] Peterson et al.—Phylogeny of Muhlenberginiinae American species. The phylogenetic arrangement of the various tribes, subtribes, and genera in our analysis is similar to that found in Peterson et al. (2010) in which the Zoysieae is sister to the Cynodonteae, and within the Cynodonteae nested clades of the Aeluropodinae and Triodiinae are first, followed by the Orcuttiinae (not included), Tridentinae, Eleusininae, Tripogoninae (not included), Pappophorinae (not included), Traginae, an almost entirely New World clade with the Allolepis-JouveaHilariinae sister to the Monanthochloinae-Scleropogoninae, Sohnsia filifolia, Lepturidium insulare Hitchc. & Ekman (not included), and the remaining Muhlenbergiinae. Within the Muhlenbergiinae, multiple independent radiations to South America have occurred one or more times in each of the three subgenera and two sections (blue and purple taxa in Figs. 1–3), and 15 species occur in both North and South America. The study of amphitropical disjunctions within the Muhlenbergiinae has indicated a North American origin and recent introduction into South America for at least three species (Peterson and Herrera Arrieta, 1995; Sykes et al., 1997; Peterson and Morrone, 1998; Peterson and Ortíz Diaz, 1998; Peterson et al., 2007a). Other plant groups with similar desert, amphitropical disjunct distributions have all been postulated to be of recent origin, i.e., late Pliocene to Pleistocene (Raven, 1963; Wen and Ickert-Bond, 2009). Within M. subg. Muhlenbergia, there is evidence for a single colonization event in southeastern Asia (red taxa in Figs. 1–3). Intercontinental disjunctions between eastern North America and eastern Asia have been investigated in insects (von Dohlen et al., 2002) and plants (Wen, 1999, 2001; Wen et al., 2002). This floristic disjunction has resulted from fragmentation and range restriction of a widespread mesophytic forest during the past that attained its intercontinental distribution via the Bering and North Atlantic land bridges (e.g., Manchester, 1999; reviewed in Wen, 1999, 2001). Because the Asian Muhlenbergia clade is deeply nested, it seems likely that these species attained their current distribution recently, at least post Pleistocene. Estimates of introduction dates will be the topic of a forthcoming biogeographic study with the use of additional markers and a more complete sample of the species in the subtribe. Taxonomy— Because our molecular analysis renders Muhlenbergia paraphyletic, we propose incorporating Aegopogon, Bealia, Blepharoneuron, Chaboissaea, Lycurus, Pereilema, Redfieldia, Schaffnerella, and Schedonnardus within Muhlenbergia. Muhlenbergia is the oldest name. Expansion of the circumscription to include these nine genera within Muhlenbergia requires the least amount of nomenclatural changes and still allows us to recognize a strongly supported monophyletic and morphologically cohesive unit. A complete classification for the Chloridoideae of the New World can be found in Soreng et al. (2009), and an attempt to place most genera within the subfamily into the four recognized tribes is found in Peterson et al. (2010). Below, we list all species in these nine genera and provide their name in Muhlenbergia. Our analysis also supports the recognition of five major clades within Muhlenbergia, and for consistency in rank, we propose two new subgeneric combinations below. Muhlenbergia alopecuroides (Griseb.) P. M. Peterson & Columbus, Madroño 55(2): 159. 2008. Basionym: Lycurus alopecuroides Griseb., Abh. Königl. Ges. Wiss. Göttingen 19: 255–256. 1874. Heterotypic synonym: Pleopogon setosum Nutt., Proc. Acad. Nat. Sci. Philadelphia 4: 25. 1848. Lycurus setosus (Nutt.) C. Reeder, Phytologia 57: 287. 1985. non Muhlenbergia setosa (Kunth) Trin. 1543 Muhlenbergia ammophila P. M. Peterson, nom. nov. Replaced name: Graphephorum flexuosum Thurb. ex A. Gray, Proc. Acad. Nat. Sci. Philadelphia 1863: 78. 1864. Redfieldia flexuosa (Thurb. ex A. Gray) Vasey, Bull. Torrey Bot. Club 14: 133. 1887. non Muhlenbergia flexuosa Hitchc. Notes: The species is usually found growing on sand hills and dunes; therefore, it seems appropriate to emphasize its habitat requirement by using the epithet “ammophila” or sand loving. Muhlenbergia atacamensis Parodi, Revista Argent. Agron. 15: 248. 1948. Chaboissaea atacamensis (Parodi) P. M. Peterson & Annable, Madroño 39(1): 19. 1992. Muhlenbergia subg. Bealia (Scribn.) P. M. Peterson, comb. stat. nov. Basionym: Bealia Scribn., The True Grasses 104, f. 45a. 1890. Muhlenbergia sect. Bealia (Scribn.) Pilg., Die Natülichen Planzenfamilien, Zweite Auflage 14d: 71. 1956. Muhlenbergia beyrichianum Kunth, Enum. Pl. 1: 200. 1833. Pereilema beyrichianum (Kunth) Hitchc., Contr. U. S. Natl. Herb. 24(8): 385. 1927. Muhlenbergia biloba Hitchc., Contr. U. S. Natl. Herb. 17(3): 294. 1913. Replaced name: Bealia mexicana Scribn., The True Grasses 103, f. 45a. 1890. non Muhlenbergia mexicana (L.) Trin., Gram. Unifl. Sesquifl. 189, 190, 297, t. 5, f. 8. 1824. Muhlenbergia bryophilus (Döll) P. M. Peterson, Caldasia 31(2): 279. 2009. Basionym: Aegopogon bryophilus Döll, Fl. Bras. 2(3): 239. 1880. Muhlenbergia cenchroides (Humb. & Bonpl. ex Willd.) P. M. Peterson, Caldasia 31(2): 280. 2009. Basionym: Aegopogon cenchroides Humb. & Bonpl. ex Willd., Sp. Pl. 4(2): 899. 1806. Muhlenbergia columbi P. M. Peterson, nom. nov. Replaced name: Schaffnera gracilis Benth., Hooker’s Icon. Pl. 14: 59. T. 1378. 1882. later near hom., non Schaffneria Moore (1857). non Muhlenbergia gracilis (Kunth) Trin. Schaffnerella gracilis (Benth.) Nash, N. Amer. Fl. 17(2): 141. 1912. Notes: The specific epithet commemorates J. Travis Columbus who led a trip to San Luis Potosí, Mexico and was the first to collect this enigmatic species again more than 120 yr after the original collections by J. G. Schaffner between 1876 and 1880 (Columbus et al., 2002). Muhlenbergia decumbens Swallen, Bol. Soc. Bot. Mexico 23: 30–32. F. 4. 1959. Chaboissaea decumbens (Swallen) Reeder & C. Reeder, Phytologia 65(2): 156. 1988. Muhlenbergia diandra (R. W. Pohl) P. M. Peterson, comb. nov. Basionym: Pereilema diandrum R. W. Pohl, Novon 2(2): 102. 1992. Muhlenbergia geminiflora (Kunth) P. M. Peterson, comb. nov. Basionym: Aegopogon geminiflorus Kunth, Nov. Gen. Sp. (quarto ed.) 1: 133, t. 43. 1816. Heterotypic synonyms: Lamarkia tenella DC., Cat. Pl. Hort. Monsp. 120. 1813. Aegopogon tenellus (DC.) Trin., Gram. Unifl. Sesquifl. 164. 1824. non Muhlenbergia tenella (Kunth) Trin. Muhlenbergia ligulata (E. Fourn.) Scribn. & Merr., Bull. Div. Agrostol. USDA 24. 19. 1901. Basionym: Chaboissaea ligulata E. Fourn., Mexic. Pl. 2: 112t. 1. 1886. Muhlenbergia paniculata (Nutt.) P. M. Peterson, comb. nov. Basionym: Lepturus paniculatus Nutt., Gen. N. Amer. Pl. 1: 81. 1818. Schedonnardus paniculatus (Nutt.) Trel., Annual Rep. Geol. Surv. Arkansas 1888(4): 236. 1891. Muhlenbergia pereilema P. M. Peterson, Caldasia 31(2): 293. 2009. Replaced name: Pereilema crinitum J. Presl, Reliq. Haenk. 1(4–5): 233, t. 37, f. a–f. 1830. non Muhlenbergia crinita (L. f.) Trin. Muhlenbergia phalaroides (Kunth) P. M. Peterson, Caldasia 31(2): 294. 2009. Basionym: Lycurus phalaroides Kunth, Nov. Gen. Sp. (quarto ed.) 1: 142. 1816. 1544 American Journal of Botany [Vol. 97 Fig. 3. Phylogram of best maximum likelihood tree from analysis of combined plastid and ITS data. Numbers above branches represent bootstrap values; numbers below branches are posterior probability values. (A) Detail of upper portion and (B) lower portion of phylogram. Abbreviations for subtribes: A = Aeluropodinae, B = Boutelouinae, E = Eleusininae, H = Hilariinae, Mo = Monanthochloinae, Sc = Scleropogoninae, Td = Triodiinae, Tg = Traginae, Tt = Tridentinae. Taxon color indicates native distribution: green = North America, blue = South America, purple = North and South America, red = southeast Asia. September 2010] Peterson et al.—Phylogeny of Muhlenberginiinae 1545 American Journal of Botany 1546 Muhlenbergia phleoides (Kunth) P. M. Peterson, comb. nov. Basionym: Lycurus phleoides Kunth, Nov. Gen. Sp. (quarto ed.) 1: 142, t. 45. 1816. Muhlenbergia plumosa P. M. Peterson, nom. nov. Replaced name: Pereilema ciliatum E. Fourn, Mexic. Pl. 2: 93. 1886 non Muhlenbergia ciliata (Kunth) Trin. Notes: The new name emphasizes the small feathery hairs on the surface of the fascicled spikelets and the sterile bristles that surround the fertile spikelets. Muhlenbergia subg. Pseudosporobolus (Parodi) P. M. Peterson, comb. stat. nov. Basionym: Muhlenbergia unranked Pseudosporobolus Parodi, Physis. Revista de la Sociedad Argentina de Ciencias Naturales 9: 207. 1928. M. sect. Pseudosporobolus (Parodi) Pilg., Die Natülichen Planzenfamilien, Zweite Auflage 14d: 71. 1956. Lectotype: Muhlenbergia fastigiata (J. Presl) Henrard, designated here. Parodi (1928) and Pilger (1956) did not explicitly indicate the type species for this taxon. Muhlenbergia shepherdii (Vasey) Swallen, Contr. U. S. Natl. Herb. 29(4): 204. 1947. Basionym: Sporobolus shepherdii Vasey, Bull. Torrey Bot. Club 14: 8. 1887. Blepharoneuron shepherdii (Vasey) P. M. Peterson & Annable, Syst. Bot. 15: 519. 1990. Muhlenbergia solisii (G. A. Levin) P. M. Peterson, comb. nov. Basionym: Aegopogon solisii G. A. Levin, Mem. San Diego Soc. Nat. Hist. 16: 61. 1989. Muhlenbergia subbiflora Hitchc., N. Amer. Fl. 17(6): 437. 1935. Chaboissaea subbiflora (Hitchc.) Reeder & C. Reeder, Phytologia 65(2): 156. 1988. Muhlenbergia tricholepis (Torr.) P. M. Peterson, comb.nov. Basionym: Vilfa tricholepis Torr., Pacif. Railr. Rep. 4(5): 155. 1857. Blepharoneuron tricholepis (Torr.) Nash, Bull. Torrey Bot. Club 25(2): 88. 1898. LITERATURE CITED Brown, W. V. 1977. The Kranz syndrome and its subtypes in grass systematics. Memoirs of the Torrey Botanical Club 23: 1–97. Clayton, W. D., and S. A. Renvoize. 1986. Genera graminum, grasses of the world. Her Majesty’s Stationery Office, London, UK. Columbus, J. T., H. L. Bell, R. Cerros Tlatilpa, M. P. Griffith, and J. M. Porter. 2002. Schaffnerella rediscovered! (Gramineae, Chloridoideae). Aliso 20: 45–50. Columbus, J. T., R. Cerros Tlatilpa, M. S. Kinney, M. E. SiqueirosDelgado, H. L. Bell, M. P. Griffith, and N. F. Refulio Rodríguez. 2007. Phylogenetics of Chloridoideae (Gramineae): A preliminary study based on nuclear ribosomal internal transcribed spacer and chloroplast trnL-F sequences. Aliso 23: 565–579. Columbus, J. T., M. S. Kinney, R. Pant, and M. E. Siqueiros D. 1998. Cladistic parsimony analysis of internal transcribed spacer region (nrDNA) sequences of Bouteloua and relatives (Gramineae: Chloridoideae). Aliso 17: 99–130. Columbus, J. T., P. M. Peterson, N. F. Refulio Rodríguez, R. Cerros Tlatilpa, and M. S. Kinney. 2010. Phylogenetics of Muhlenbergiinae (Poaceae, Chloridoideae, Cynodonteae) based on ITS and trnL-F DNA sequences. In O. Seberg, G. Petersen, A. S. Barfod, and J. I. Davis [eds.], Diversity, phylogeny, and evolution in the monocotyledons, 477–495. Aarhus University Press, Aarhus, Denmark. Dengler, N. G., R. E. Dengler, and P. W. Hattersley. 1986. Comparative bundle sheath and mesophyll differentiation in the leaves of the C4 grasses Panicum effusum and P. bulbosum. American Journal of Botany 73: 1431–1442. Duvall, M. R., P. M. Peterson, and A. H. Christensen. 1994. Alliances of Muhlenbergia (Poaceae) within New World Eragrostideae are identified by phylogenetic analysis of mapped restriction sites from plastid DNAs. American Journal of Botany 81: 622–629. Edwards, E. J., C. P. Osborne, C. A. E. Strömberg, S. A. Smith and C4 Grasses Consortium [E. J. Edwards, C. P. Osborne, C. A. E. Strömberg, S. A. Smith W. J. Bond, P. A. Christin, A. B. Cousins, [Vol. 97 et al.]. 2010. The origins of C4 grasslands: Integrating evolutionary and ecosystem science. Science 328: 587–591. Farris, J. S., M. Källersjö, A. G. Kluge, and C. Bult. 1994. Testing significance of incongruence. Cladistics 10: 315–319. Felsenstein, J. 1985. Confidence limits on phylogenies: An approach using the bootstrap. Evolution 39: 783–791. Gibson, D. J. 2009. Grasses and grassland ecology. Oxford University Press, New York, New York, USA. Giussani, L. M., J. H. Cota-Sánchez, F. O. Zuloaga, and E. A. Kellogg. 2001. A molecular phylogeny of the grass subfamily Panicoideae (Poaceae) shows multiple origins of C4 photosynthesis. American Journal of Botany 88: 1993–2012. Gustafson, D. J., and P. M. Peterson. 2007. Re-examination of the Muhlenbergia capillaries, M. expansa, and M. sericea (Poaceae: Muhlenbergiinae). Journal of the Botanical Research Institute of Texas 1: 85–89. Gutierrez, M., V. E. Gracen, and G. E. Edwards. 1974. Biochemical and cytological relationships in C4 plants. Planta 119: 279–300. Hall, T. A. 1999. BioEdit: A user-friendly biological sequence alignment editor and analysis program for Windows 95/98/NT. Nucleic Acids Symposium Series 41: 95–98. Hattersley, P. W., and L. Watson. 1976. C4 grasses: An anatomical criterion for distinguishing between NADP-malic enzyme species and PCK or NAD-malic enzyme species. Australian Journal of Botany 24: 297–308. Hattersley, P. W., and L. Watson. 1992. Diversification of photosynthesis. In G. P. Chapman [ed.], Grass evolution and domestication, 38–116. Cambridge University Press, Cambridge, UK. Herrera Arrieta, Y. 1998. A revision of the Muhlenbergia montana (Nutt.) Hitchc. complex (Poaceae: Chloridoideae). Brittonia 50: 23–50. Herrera Arrieta, Y., and W. F. Grant. 1993. Correlation between generated morphological character data and flavonoid content of species in the Muhlenbergia montana complex. Canadian Journal of Botany 71: 816–826. Herrera Arrieta, Y., and W. F. Grant. 1994. Anatomy of the Muhlenbergia montana (Poaceae) complex. American Journal of Botany 81: 1038–1044. Herrera Arrieta, Y., and P. M. Peterson. 2007. Muhlenbergia (Poaceae) de Chihuahua, Mexico. Sida. Botanical Miscellany 29: 1–109. Hilu, K. W., and L. A. Alice. 2001. A phylogeny of Chloridoideae (Poaceae) based on matK sequences. Systematic Botany 26: 386–405. Hitchcock, A. S. 1935. Manual of grasses of the United States. Miscellaneous Publication 200. U. S. Department of Agriculture, Washington, D.C., USA. Huelsenbeck, J. P., and F. R. Ronquist. 2001. MRBAYES: Bayesian inference of phylogenetic trees. Bioinformatics 17: 754–755. Kimura, M. 1981. Estimation of evolutionary distances between homologous nucleotide sequences. Proceedings of the National Academy of Sciences, USA 78: 454–458. Laegaard, S., and I. Sánchez Vega. 1990. Three new species of Muhlenbergia and Uniola (Poaceae) from northern Peru. Nordic Journal of Botany 10: 437–441. Levin, G. A., and R. Moran. 1989. The vascular flora of Isla Socorro, Mexico. San Diego Society of Natural History Memoir 16: 1–66. Manchester, S. R. 1999. Biogeographical relationships of North American Tertiary floras. Annals of the Missouri Botanical Garden 86: 472–522. Morden, C. W. 1985. A biosystematic study of the Muhlenbergia repens complex (Poaceae). Ph.D. dissertation, Texas A&M University, College Station, Texas, USA. Morden, C. W., and S. L. Hatch. 1984. Cleistogamy in Muhlenbergia cuspidata (Poaceae). Sida 10: 254–255. Morden, C. W., and S. L. Hatch. 1987. Anatomical study of the Muhlenbergia repens complex (Poaceae: Chloridoideae: Eragrostideae). Sida 12: 347–359. Morden, C. W., and S. L. Hatch. 1996. Morphological variation and synopsis of the Muhlenbergia repens complex (Poaceae). Sida 17: 349–365. Nash, G. V. 1898. New or noteworthy American grasses VIII. Bulletin of the Torrey Botanical Club 25: 83–89. September 2010] Peterson et al.—Phylogeny of Muhlenberginiinae Nixon, K. C. 2002. WinClada ver. 1.00.08. Computer program published by the author. Ithaca, New York, USA. Nylander, J. A. 2002. MrModeltest v.1.1b. Computer program distributed by the author. Department of Systematic Zoology, Uppsala University, Uppsala, Sweden. Parodi, L. R. 1928. Sinopsis de las gramíneas Argentinas del género Muhlenbergia. Physis Revista de la Sociedad Argentina de Ciencias Naturales 9: 205–222. Peterson, P. M. 1988a. Systematics of the annual Muhlenbergia (Poaceae). PhD. dissertation, Washington State University, Pullman, Washington, USA. Peterson, P. M. 1988b. Chromosome numbers in the annual Muhlenbergia (Poaceae). Madroño 35: 320–324. Peterson, P. M. 1989a. Lemma micromorphology in the annual Muhlenbergia (Poaceae). Southwestern Naturalist 34: 61–71. Peterson, P. M. 1989b. A re-evaluation of Bealia mexicana (Poaceae: Eragrostideae). Madroño 36: 260–265. Peterson, P. M. 2000. Systematics of the Muhlenbergiinae (Chloridoideae: Eragrostideae). In S. W. L. Jacobs and J. Everett [eds.]. Grasses: Systematics and evolution, 195––212. Commonwealth Scientific and Research Organization [CSIRO] Publishing, Melbourne, Australia. Peterson, P. M. 2003. Muhlenbergia. In M. E. Barkworth, K. M. Capels, S. Long, and M. B. Piep [eds.], Magnoliophyta: Commelinidae (in part): Poaceae, part 2, Flora of North America north of Mexico, vol. 25, 145–201. Oxford University Press, New York, New York, USA. Peterson, P. M., and C. R. Annable. 1990. A revision of Blepharoneuron (Poaceae: Eragrostideae). Systematic Botany 15: 515–525. Peterson, P. M., and C. R. Annable. 1991. Systematics of the annual species of Muhlenbergia (Poaceae: Eragrostideae). Systematic Botany Monographs 31: 1–109. Peterson, P. M., and C. R. Annable. 1992. A revision of Chaboissaea (Poaceae: Eragrostideae). Madroño 39: 8–30. Peterson, P. M., and C. R. Annable. 2003. Blepharoneuron. In M. E. Barkworth, K. M. Capels, S. Long, and M. B. Piep [eds.], Magnoliophyta: Commelinidae (in part): Poaceae, part 2, Flora of North America north of Mexico, vol. 25, 47, 48, 50. Oxford University Press, New York, New York, USA. Peterson, P. M., C. R. Annable, and V. R. Franceschi. 1989. Comparative leaf anatomy of the annual Muhlenbergia (Poaceae). Nordic Journal of Botany 8: 575–583. Peterson, P. M., and J. T. Columbus. 2009. Muhlenbergia tarahumara (Poaceae: Chloridoideae: Cynodonteae: Muhlenbergiinae), a new species from Chihuahua, Mexico. Journal of the Botanical Research Institute of Texas 3: 527–534. Peterson, P. M., J. T. Columbus, and S. J. Pennington. 2007a. Classification and biogeography of New World grasses: Chloridoideae. Aliso 23: 580–594. Peterson, P. M., M. R. Duvall, and A. H. Christensen. 1993. Allozyme differentiation among Bealia mexicana, Muhlenbergia argentea, and M. lucida. Madroño 40: 148–160. Peterson, P. M., and Y. Herrera Arrieta. 1995. Allozyme variation in the amphitropical disjunct Chaboissaea (Poaceae: Eragrostideae). Madro˜o 42: 427–449. Peterson, P. M., and Y. Herrera Arrieta. 2001. A leaf blade anatomical survey of Muhlenbergia (Poaceae: Muhlenbergiinae). Sida 19: 469–506. Peterson, P. M., and O. Morrone. 1998. Allelic variation in the amphitropical disjunct Lycurus setosus (Poaceae: Muhlenbergiinae). Madroño 44: 334–346. Peterson, P. M., and J. J. Ortíz Diaz. 1998. Allelic variation in the amphitropical disjunct Muhlenbergia torreyi (Poaceae: Muhlenbergiinae). Brittonia 50: 381–391. Peterson, P. M., and L. H. Rieseberg. 1987. Flavonoids of the annual Muhlenbergia. Biochemical Systematics and Ecology 15: 647–652. Peterson, P. M., K. Romaschenko, and G. Johnson. 2010. A classification of the Chloridoideae (Poaceae) based on multi-gene phylogenetics trees. Molecular Phylogenetics and Evolution 55: 580–598. Peterson, P. M., R. J. Soreng, G. Davidse, T. S. Filgueiras, F. O. Zuloaga, and E. J. Judziewicz. 2001. Catalogue of New World 1547 grasses (Poaceae): II. Subfamily Chloridoideae. Contributions from the United States National Herbarium 41: 1–255. Peterson, P. M., J. Valdés Reyna, and Y. Herrera Arrieta. 2007b. Muhlenbergiinae (Poaceae: Chloridoideae: Cynodonteae): From northeastern Mexico. Journal of the Botanical Research Institute of Texas 1: 933–1000. Peterson, P. M., R. D. Webster, and J. Valdés Reyna. 1995. Subtribal classification of the New World Eragrostideae (Poaceae: Chloridoideae). Sida 16: 529–544. Peterson, P. M., R. D. Webster, and J. Valdés Reyna. 1997. Genera of New World Eragrostideae (Poaceae: Chloridoideae). Smithsonian Contributions to Botany 87: 1–50. Pilger, R. 1956. Gramineae II. Unterfamilien: Micrairoideae, Eragrostideae, Oryzoideae, Olyroideae. In A. Engler and J. Prantl [eds.], Die natürlichen Pflanzenfamilien, 2nd ed., vol. 14, 1–168. Duncker and Humblot, Berlin, Germany. Pohl, R. W. 1969. Muhlenbergia subgenus Muhlenbergia (Gramineae) in North America. American Midland Naturalist 82: 512–542. Posada, D., and K. A. Crandall. 1998. MODELTEST: Testing the model of DNA substitution. Bioinformatics 14: 817–818. Raven, P. H. 1963. Amphitropical relationships in the floras of North and South America. Quarterly Review of Biology 38: 151–177. Reeder, C. G. 1985. The genus Lycurus in North America. Phytologia 57: 283–291. Reeder, C. G., and J. R. Reeder. 1995. The resurrection of a species: Muhlenbergia straminea (Gramineae). Phytologia 78: 417–427. Reeder, J. R. 1957. The embryo in grass systematics. American Journal of Botany 44: 756–768. Reeder, J. R. 1976. Systematic position of Redfieldia (Gramineae). Madroño 23: 434–438. Romaschenko, K., P. M. Peterson, R. J. Soreng, N. Garcia-Jacas, O. Futorna, and A. Susanna. 2010. Phylogenetics of Stipeae (Poaceae: Pooideae) based on plastid and nuclear DNA sequences. In O. Seberg, G. Petersen, A. S. Barfod, and J. I. Davis [eds.], Diversity, phylogeny, and evolution in the monocotyledons, 513–539. Aarhus University Press, Aarhus, Denmark. Ronquist, F., J. P. Huelsenbeck, and P. van der Mark. 2005. MrBayes 3.1 manual, draft 5/26/2005. Website http://mrbayes.csit. fsu.edu/mb3.1_manual.pdf. Sánchez, E., and Z. E. Rúgolo de Agrasar. 1986. Estudio taxonómica sobre género Lycurus (Gramineae). Parodiana 4: 267–310. Shaw, J., E. B. Lickey, J. T. Beck, S. B. Farmer, W. Liu, J. Miller, K. C. Siripun, C. T. Winder, E. E. Schilling, and R. L. Small. 2005. The tortoise and the hare II: Relative utility of 21 noncoding chloroplast DNA sequences for phylogenetic analysis. American Journal of Botany 92: 142–166. Shaw, J., E. B. Lickey, E. E. Schilling, and R. L. Small. 2007. Comparison of whole chloroplast genome sequences to choose noncoding regions for phylogenetic studies in Angiosperms: The tortoise and the hare III. American Journal of Botany 94: 275–288. Soderstrom, T. R. 1967. Taxonomic study of subgenus Podosemum and section Epicampes of Muhlenbergia (Gramineae). Contributions from the United States National Herbarium 34: 75–189. Soreng, R. J., G. Davidse, P. M. Peterson, F. O. Zuloaga, E. J. Judziewicz, T. S. Filgueiras, and O. Morrone. 2009. Classification of New World grasses [updated 2 September 2009]. Website http://www.tropicos. org/docs/meso/grassclassificationstrippedgd1Apr2010.htm. Soreng, R. J., J. I. Davis, and M. A. Voionmaa. 2007. A phylogenetic analysis of Poaceae tribe Poeae sensu lato based on morphological characters and sequence data from three plastid-encoded genes: Evidence for reticulation, and a new classification for the tribe. Kew Bulletin 62: 425–454. Stebbins, G. L., and B. Crampton. 1961. A suggested revision of the grass genera of temperate North America. In Recent advances in botany, from lectures & symposia presented to the IX International Botanical Congress, Montreal, 1959, vol. 1: 133−145. University of Toronto Press, Toronto, Canada. Swofford, D. L. 2000. PAUP*: Phylogenetic analysis using parsimony (*and other methods), version 4. Sinauer, Sunderland, Massachuesetts, USA. 1548 American Journal of Botany Sykes, G. R., A. H. Christensen, and P. M. Peterson. 1997. A chloroplast DNA analysis of Chaboissaea (Poaceae: Eragrostideae). Systematic Botany 22: 291–302. Tavaré, S. 1986. Some probabilistic and statistical problems in analysis of DNA sequences. In R. M. Miura [ed.], Some mathematical questions in biology: DNA sequence analysis, vol. 17. American Mathematical Society, Ann Arbor, Michigan, USA. Türpe, A. M. 1973. Anatomía foliar en Aegopogon. Lilloa 33: 261–280. von Dohlen, C. D., U. Kurosu, and S. Aoki. 2002. Phylogenetics and evolution of the eastern Asian–eastern North American disjunct aphid tribe, Hormaphidini (Hemiptera: Aphididae). Molecular Phylogenetics and Evolution 23: 257–267. Wen, J. 1999. Evolution of eastern Asian and eastern North American disjunct distributions in flowering plants. Annual Review of Ecology and Systematics 30: 421–455. Wen, J. 2001. Evolution of eastern Asian–eastern North American biogeographic disjunctions: A few additional issues. International Journal of Plant Sciences 162: S117–S122. [Vol. 97 Wen, J., and S. M. Ickert-Bond. 2009. Evolution of the Madrean–Tethyan disjunctions and the North and South American amphitropical disjunctions in plants. Journal of Systematics and Evolution 47: 331–348. Wen, J., P. P. Lowry II, J. L. Walck, and K. O. Yoo. 2002. Phylogenetic and biogeographic diversification in Osmorhiza (Apiaceae). Annals of the Missouri Botanical Garden 89: 414–428. World Resources. 2000. People and ecosystems: The fraying web of life. World Resources Institute in collaboration with the United Nations Development Program, United Nations Environment Program, and the World Bank, Washington, D.C., USA. Wu, Z. L., and P. M. Peterson. 2006. Muhlenbergia. In Z. Y. Wu, P. H. Raven, and D. Y. Hong [eds.], Flora of China: Poaceae, vol. 22, 486– 487. Science Press, Beijing, China and Missouri Botanical Garden Press, St. Louis, Missouri, USA. Zwickl, D. J. 2006. Genetic algorithm approaches for the phylogenetic analysis of large biological sequence datasets under the maximum likelihood criterion. Ph.D. dissertation, University of Texas, Austin, Texas, USA. Taxon Voucher Country ndhF rpl32-trnL rps16-trnK rps3 ITS rps16 intron ndhA intron GU359613 GU360011 GU360578 GU360143 GU359259 GU360274 GU359403 Peterson 22044 & Saarela Weinert s.n. & Mosawi Mexico Iraq GU359592 GU359591 GU360012 GU360013 GU360577 GU360576 GU360128 GU360085 GU359260 GU359261 GU360278 GU360284 GU359392 GU359391 Hitchcock 7541 Mexico GU359577 GU360015 GU360573 GU360088 GU359264 GU360318 GU359388 Chalmers 5 Australia GU359585 GU359861 GU360567 GU360095 GU359286 GU360311 GU359421 Anson s.n. Australia GU359584 GU359860 GU360566 GU360113 GU359272 GU360310 GU359420 Peterson 7946, Annable & Herrera Melix 570 & Cherobini Mexico — GU359859 GU360550 GU360098 GU359258 GU360309 — GU359582 GU359857 GU360579 GU360100 GU359275 — — Peterson 20013& Sanchez Alvarado Peterson 22452 & Saarela Mexico — HM143139 HM143625 HM143242 HM143038 HM143529 HM143346 Mexico GU359580 GU359854 GU360560 GU360102 GU359277 GU360320 GU359419 Peterson 22099 & Saarela Mexico GU359576 GU359853 GU360559 GU360103 GU359278 GU360305 GU359418 Peterson 21994 & Saarela Mexico GU359570 GU359852 GU360558 GU360104 GU359279 GU360304 GU359417 Peterson 21423, Saarela & Stančik Chaboissaea atacamensis Peterson 19626, Soreng, (Parodi) P. M. Peterson & Annable Salariato, & Panizza, Chaboissaea ligulata E. Fourn. Peterson 22416 & Saarela Chaboissaea subbiflora (Hitchc.) Reeder Peterson 21158, Saarela, & C. Reeder Rosen & Reid Chloris radiata (L.) Sw. Peterson 22278 & Saarela Crypsis aculeata (L.) Aiton Soreng 5469 & Peterson Cynodon hirsutus Stent Smook 6616 Dasyochloa pulchella (Kunth) Peterson 21992 & Saarela Willd. ex Rydb. Distichlis spicata (L.) Greene Peterson 19309, Soreng, Salariato & Panizza Eleusine indica (L.) Gaetrn. Peterson 21362, Saarela & Flores Villegas Erioneuron avenaceum (Kunth) Tateoka Peterson 19329, Soreng, Salariato & Panizza Gouinia paraguayensis (Kuntze) Parodi Peterson 11526 & Annable Gymnopogon grandiflorus Peterson 16642 & Roseng., B. R. Arill. & Izag. Refulio-Rodriguez Hilaria cenchroides Kunth Peterson 22339 & Saarela Jouvea pilosa (J. Presl) Scribn. Peterson 11017 & Annable Lepturus repens R. Br. Whistler 9853 Mexico GU359567 GU359848 GU360606 GU360133 GU359232 GU360296 GU359383 Argentina GU359729 GU359879 GU360595 GU360115 GU359344 GU360489 GU359382 Mexico Mexico GU359718 GU359707 GU359863 GU359877 GU360551 GU360518 GU360069 GU360036 GU359273 GU359318 GU360440 GU360439 GU359381 GU359428 Mexico China South Africa Mexico GU359724 GU359573 GU359751 GU359689 GU359872 GU359841 GU359876 GU359864 GU360513 GU360599 GU360594 GU360505 GU360048 GU360140 GU360135 GU360039 GU359321 GU359238 GU359229 GU359330 GU360434 GU360402 GU360452 GU360482 GU359366 GU359362 GU359358 GU359369 Argentina GU359695 GU359801 GU360499 GU360032 GU359346 GU360475 GU359478 Mexico GU359698 GU359797 GU360496 GU360031 GU359338 GU360472 GU359473 Argentina GU359773 GU359822 GU360525 GU360063 GU359310 GU360403 GU359441 Argentina Peru GU359732 GU359733 GU359817 GU359816 GU360504 GU360581 GU360058 GU360057 GU359314 GU359200 GU360384 GU360383 GU359437 GU359436 Mexico Mexico Diego Garcia Island Mexico GU359736 GU359737 GU359730 GU359813 GU359812 GU359893 GU360697 GU360696 GU360691 GU360055 GU360173 GU360228 GU359143 GU359144 GU359150 GU360380 GU360379 GU360428 GU359424 GU359433 GU359427 GU359744 GU359976 GU360688 GU360224 GU359152 GU360426 GU359425 Mexico GU359745 South Africa GU359746 GU359975 GU359972 GU360687 GU360670 GU360223 GU360206 GU359153 GU359155 GU360425 GU360424 GU359451 GU359453 Blepharidachne benthamiana (Hack.) Hitchc. Blepharoneuron shepherdii (Vasey) P. M. Peterson & Annable Blepharoneuron shepherdii (Vasey) P. M. Peterson & Annable Blepharoneuron tricholepis (Torr.) Nash Bouteloua aristidoides (Kunth) Griseb. Bouteloua uniflora Vasey Lycurus setosus (Nutt.) C. Reeder Lycurus setosus (Nutt.) C. Reeder Microchloa caffra Nees Peterson 20960, Saarela, Lara Contreras & Reyna Alvarez Peterson 22008 Smook 10441 Argentina 1549 Mexico Peterson et al.—Phylogeny of Muhlenberginiinae Peterson 22045 & Saarela Aegopogon cenchroides Humb. & Bonpl. ex Willd. Aegopogon tenellus (DC.) Trin. Aeluropus lagopoides (L.) Trin. ex Thwaites Allolepis texana (Vasey) Soderstr. & H. F. Decker Astrebla pectinata (Lindl.) F. Muell. ex Benth. Austrochloris dichanthioides (Everist) Lazarides Bealia mexicana Scribn. September 2010] Appendix 1. Specimens sampled, vouchers (all housed at the United States National Herbarium, US), country, and GenBank accessions for DNA sequences. Sequences generated by this study are in boldfaced type; all other sequences are from Peterson et al. (2010). Monanthochloe littoralis Engelm. Monelytrum luederitzianum Hack. Mosdenia phleoides (Hack.) Stent Muhlenbergia alamosae Vasey Muhlenbergia andina (Nutt.) Hitchc. Muhlenbergia angustata (J. Presl) Kunth Muhlenbergia angustata (J. Presl) Kunth Muhlenbergia annua (Vasey) Swallen Muhlenbergia appressa C. O. Goodd. Muhlenbergia arenacea (Buckley) Hitchc. Muhlenbergia arenicola Buckley Muhlenbergia curtifolia Scribn. Muhlenbergia cuspidata (Torr. ex Hook.) Rydb. Muhlenbergia depauperata Scribn. Muhlenbergia distichophylla (J. Presl) Kunth Muhlenbergia dubia E. Fourn. Muhlenbergia dubia E. Fourn. Muhlenbergia dumosa Scribn. ex Vasey Muhlenbergia durangensis Y. Herrera Peterson 19947 & Lara-Contreras Peterson 22095 & Saarela Peterson 22173 & Saarela Peterson 15208 & Cayouette Peterson 13386 & Knowles Peterson 15452, Soreng, Finot & Judziewicz Peterson 4760 & Annable Peterson 22023 & Saarela McVaugh 22930 Peterson 5013 & Barron Peterson 14236, Weakley & LeBlond Peterson 21965, Soreng & Montoya Quino Peterson 22193 & Saarela Peterson 10768, Annable & Valdes Reyna Peterson 5631 & Annable Hill 35331 Peterson 21293, Saarela & Flores Villegas Peterson 15913 & Valdes Reyna Peterson 15885 & Valdes Reyna Peterson 21105 & Saarela Peterson 13438, Knowles, Dietrich & Braxton Peterson 13644, Knowles, Dietrich, Braxton & Gonzalez Elizondo Peterson 22164 & Saarela Peterson 22188 & Saarela Peterson 22096 & Saarela ndhF rpl32-trnL rps16-trnK rps3 ITS rps16 intron ndhA intron Mexico South Africa South Africa Mexico USA GU359748 GU359749 GU359750 HM143436 HM143437 GU359970 GU359969 GU359967 HM143140 HM143141 GU360699 GU360682 GU360681 HM143626 — GU360235 GU360218 GU360216 HM143243 HM143244 GU359157 GU359158 GU359159 HM143039 HM143040 GU360422 GU360421 GU360420 HM143530 HM143531 GU359460 GU359459 GU359458 HM143347 HM143348 Peru HM143438 HM143142 HM143627 HM143245 HM143041 HM143532 HM143349 Peru HM143439 HM143143 HM143628 HM143246 HM143042 HM143533 HM143350 Mexico USA Mexico HM143440 GU359618 GU359619 HM143144 GU359962 GU359961 HM143629 GU360676 GU360675 HM143247 GU360211 GU360210 HM143043 GU359164 GU359165 HM143534 GU360415 GU360414 HM143351 GU359443 GU359452 Mexico GU359620 GU359960 GU360674 GU360209 GU359166 GU360413 GU359462 Mexico Mexico Mexico Mexico Chile HM143441 HM143442 HM143443 — HM143444 HM143145 HM143146 HM143147 HM143148 HM143149 HM143630 HM143631 HM143632 HM143633 HM143634 HM143248 HM143249 HM143250 HM143251 HM143252 HM143044 HM143045 HM143046 HM143047 HM143048 HM143535 HM143536 HM143537 HM143538 HM143539 HM143352 HM143353 HM143354 HM143355 HM143356 Mexico Mexico Mexico GU359621 HM143445 — GU359959 HM143150 — GU360711 HM143635 HM143636 GU360208 HM143253 — GU359167 HM143049 — GU360412 HM143540 — GU359450 HM143357 — USA USA HM143446 HM143447 HM143151 HM143152 HM143637 HM143638 HM143254 HM143255 HM143050 HM143051 HM143541 HM143542 HM143358 HM143359 Peru HM143448 HM143153 HM143639 HM143256 HM143052 HM143543 HM143360 Mexico Mexico HM143449 — HM143154 — HM143640 — HM143257 HM143258 HM143053 — HM143544 — HM143361 — USA USA HM143450 — HM143155 HM143156 HM143641 — HM143259 HM143260 HM143054 HM143055 HM143545 HM143546 HM143362 — Mexico HM143451 HM143157 HM143642 HM143261 HM143056 HM143547 HM143363 Mexico HM143452 HM143158 HM143643 HM143262 — HM143548 HM143364 Mexico HM143454 HM143159 HM143645 HM143264 HM143058 HM143549 HM143366 Mexico Mexico HM143453 HM143455 HM143160 HM143161 HM143644 HM143646 HM143263 HM143265 HM143057 HM143059 HM143550 HM143551 HM143365 HM143367 Mexico HM143456 HM143162 HM143647 HM143266 HM143060 HM143552 HM143368 Mexico HM143457 HM143163 HM143648 HM143267 HM143061 HM143553 HM143369 Mexico Mexico HM143458 GU359622 HM143164 GU359958 HM143649 GU360672 HM143268 GU360207 HM143062 GU359168 HM143554 GU360411 HM143370 GU359449 [Vol. 97 Muhlenbergia elongata Scribn. ex Beal Muhlenbergia eludens C. Reeder Muhlenbergia emersleyi Vasey Moran 10570 Smook 10031 Schweickerdt 1542 Peterson 22104 & Saarela Peterson 10432, Annable & Weinpahl Peterson 21703, Soreng, LaTorre & Rojas Fox Peterson 21958, Soreng & Montoya Quino Peterson 22022& Saarela Peterson 4183 & Annable Peterson 10624 & Annable Country American Journal of Botany Muhlenbergia argentea Vasey Muhlenbergia arizonica Scribn. Muhlenbergia arsenei Hitchc. Muhlenbergia articulata Scribn. Muhlenbergia asperifolia (Nees & Meyen ex Trin.) Parodi Muhlenbergia brandegeei C. Reeder Muhlenbergia brevis C. O. Goodd. Muhlenbergia breviseta Griseb. ex E. Fourn. Muhlenbergia californica Vasey Muhlenbergia capillaris (Lam.) Trin. Muhlenbergia caxamarcensis Lægaard & Sánchez Vega Muhlenbergia ciliata (Kunth) Trin. Muhlenbergia crispiseta Hitchc. Voucher 1550 Appendix 1. Continued Taxon Muhlenbergia expansa (Poir.) Trin. Muhlenbergia fastigiata (J. Presl) Henrard Muhlenbergia filiculmis Vasey Muhlenbergia filiformis (Thurb. ex S. Watson) Rydb. Muhlenbergia flavida Vasey Muhlenbergia flaviseta Scribn. Muhlenbergia flexuosa Hitchc. Muhlenbergia glomerata (Willd.) Trin. Muhlenbergia grandis Vasey Muhlenbergia gypsophila Reeder & C. Reeder Muhlenbergia himalayensis Hack. ex Hook. f. Muhlenbergia huegelii Trin. Muhlenbergia implicata (Kunth) Trin. Muhlenbergia iridifolia Soderstr. Muhlenbergia jaime-hintonii P. M. Peterson & Valdés-Reyna Muhlenbergia jaliscana Swallen Muhlenbergia japonica Steud. Muhlenbergia japonica Steud. Muhlenbergia jonesii (Vasey) Hitchc. Muhlenbergia lindheimeri Hitchc. Muhlenbergia longiglumis Vasey rpl32-trnL rps16-trnK rps3 ITS rps16 intron ndhA intron USA Country HM143459 HM143165 HM143650 HM143269 HM143063 HM143555 HM143371 Peru HM143460 HM143166 HM143651 HM143270 HM143064 HM143556 HM143372 Peterson 11954 & Annable Peterson 10433, Annable & Weinpahl Peterson 22237 & Saarela Peterson 22409 & Saarela Peterson 20373, Soreng & Romaschenko Peterson 22194 & Saarela Peterson 22260 & Saarela USA USA HM143461 — HM143167 HM143168 HM143652 HM143653 HM143271 HM143272 HM143065 HM143066 HM143557 HM143558 HM143373 HM143374 Mexico Mexico Peru HM143462 GU359623 HM143463 HM143169 GU359957 HM143170 HM143654 GU360685 HM143655 HM143273 GU360250 HM143274 HM143067 GU359127 HM143068 HM143559 GU360410 HM143560 HM143375 GU359448 HM143376 Mexico Mexico HM143464 GU359663 HM143171 GU359966 HM143656 GU360680 HM143275 GU360215 HM143069 GU359160 HM143561 GU360419 HM143377 GU359457 Peterson 22346 & Saarela Mexico HM143465 HM143172 HM143657 HM143276 HM143070 HM143562 HM143378 Peterson 21023, Saarela, Lara Contreras & Reyna Alvarez Peterson 21180, Saarela, Gonzalez Elizondo, Rosen & Reid Peterson 20924, Saarela & Howard Peterson 13413, Knowles, Dietrich & Braxton Peterson 15840 & Valdes Reyna Soreng 5666, Peterson & Sun Hang Soreng 5344, Peterson & Sun Hang Peterson 22266, Saarela Mexico HM143467 HM143173 HM143658 HM143278 HM143072 HM143563 HM143379 Mexico HM143466 HM143174 HM143659 HM143277 HM143071 HM143564 HM143380 USA GU359638 GU359954 GU360716 GU360253 GU359114 GU360407 GU359445 Mexico HM143468 HM143175 HM143660 HM143279 HM143073 HM143565 HM143381 Mexico HM143469 HM143176 HM143661 HM143280 HM143074 — HM143382 China HM143470 HM143177 HM143281 HM143075 HM143566 HM143383 China HM143471 HM143178 HM143661 HM143662 HM143663 HM143282 HM143076 HM143567 HM143384 Mexico HM143472 HM143179 HM143664 HM143283 HM143077 HM143568 HM143385 Peterson 6133 & Annable Peterson 15841& Valdes Reyna Peterson 6149 & Annable Soreng 5240, Peterson & Sun Hang Soreng 5301, Peterson & Sun Hang Peterson 4861 & Annable Peterson 6280 & Annable Peterson 13666, Knowles, Dietrich, Braxton & Gonzalez Elizondo Peterson 15224 & Cayouette Peterson 22047 & Saarela Peterson 22134 & Saarela Peterson 22062 & Saarela Mexico Mexico HM143473 HM143474 HM143180 HM143181 — HM143665 HM143284 HM143285 HM143078 HM143079 — HM143569 — HM143386 Mexico China HM143475 HM143477 HM143182 HM143183 HM143666 HM143667 HM143286 HM143287 HM143080 HM143081 HM143570 HM143571 HM143387 HM143388 China HM143476 HM143184 HM143668 HM143288 HM143082 HM143572 HM143389 USA USA Mexico HM143478 HM143479 — HM143185 HM143186 — HM143669 HM143670 HM143671 HM143289 HM143290 HM143291 HM143083 HM143084 — — HM143573 — HM143390 HM143391 — USA Mexico Mexico Mexico HM143480 HM143482 HM143481 GU359624 HM143187 HM143189 HM143188 GU359956 HM143672 HM143673 HM143674 GU360683 HM143292 HM143293 HM143294 GU360265 HM143085 HM143087 HM143086 GU359125 HM143574 HM143576 HM143575 GU360409 − HM143393 HM143392 GU359447 Peterson 4519 & Annable Mexico HM143483 HM143190 HM143675 HM143295 HM143088 HM143577 HM143394 Peterson 21884, Soreng & Sanchez Vega Peru HM143484 HM143191 HM143676 HM143296 HM143089 HM143578 — 1551 Muhlenbergia longiligula Hitchc. Muhlenbergia lucida Swallen Muhlenbergia lucida Swallen Muhlenbergia macroura (Kunth) Hitchc. Muhlenbergia majalcensis P. M. Peterson Muhlenbergia maxima Lægaard & Sánchez Vega Voucher Peterson et al.—Phylogeny of Muhlenberginiinae Muhlenbergia fragilis Swallen Muhlenbergia gigantea (E. Fourn.) Hitchc. Muhlenbergia gigantea (E. Fourn.) Hitchc. Muhlenbergia glauca (Nees) B. D. Jacks. Muhlenbergia glauca (Nees) B. D. Jacks. ndhF Peterson 14234, Weakley & LeBlond Peterson 21512, Soreng, LaTorre & Rojas Fox September 2010] Appendix 1. Continued Taxon Voucher Country ndhF rpl32-trnL rps16-trnK rps3 ITS rps16 intron ndhA intron USA HM143485 HM143192 HM143678 HM143298 HM143091 HM143579 HM143395 Peterson 5562 & Annable Peterson 21855 & Soreng USA Peru HM143486 HM143487 HM143193 HM143194 HM143677 HM143679 HM143297 HM143299 HM143090 HM143092 HM143580 HM143581 HM143396 HM143397 Muhlenbergia minutissima (Steud.) Swallen Muhlenbergia montana (Nutt.) Hitchc. Muhlenbergia montana (Nutt.) Hitchc. Muhlenbergia mucronata (Kunth) Trin. Muhlenbergia nigra Hitchc. Muhlenbergia palmeri Vasey Muhlenbergia palmirensis Grignon & Lægaard Muhlenbergia pauciflora Buckley Muhlenbergia pectinata C. O. Goodd. Muhlenbergia peruviana (P. Beauv.) Steud. Muhlenbergia polycaulis Scribn. Muhlenbergia porteri Scribn. ex Beal Muhlenbergia pubescens (Kunth) Hitchc. Muhlenbergia pubescens (Kunth) Hitchc. Muhlenbergia pubigluma Swallen Peterson 22012 & Saarela Mexico — HM143195 HM143680 HM143300 HM143093 — — Peterson 22046 & Saarela Peterson 22234 & Saarela Peterson 22038 & Saarela Peterson 16097 & Rosales Peterson 5478 & Annable Peterson 9317 & Judziewicz Mexico Mexico Mexico Mexico USA Ecuador HM143488 GU359705 HM143489 HM143490 HM143491 — HM143196 GU359964 HM143197 HM143198 HM143199 HM143200 HM143681 GU360678 HM143682 HM143683 HM143684 HM143685 HM143301 GU360213 HM143302 HM143303 HM143304 HM143305 HM143094 GU359162 HM143095 HM143096 HM143097 HM143098 HM143582 GU360417 HM143583 HM143584 HM143585 HM143586 HM143398 GU359455 HM143399 HM143400 HM143401 HM143402 Peterson 22048 & Saarela Peterson 22108 & Saarela Peterson 22440 & Saarela Mexico Mexico Mexico HM143492 HM143493 GU359625 HM143201 HM143202 GU359955 HM143686 HM143687 GU360713 — HM143306 GU360221 HM143099 HM143100 GU359154 HM143587 HM143588 GU360408 HM143403 HM143404 GU359446 Peterson 22092 & Saarela Peterson 19846 & Lara Contreras Peterson 21250 & Saarela Mexico Mexico HM143494 HM143495 HM143203 HM143204 HM143688 HM143689 HM143307 HM143308 HM143101 HM143102 HM143589 HM143590 — HM143405 Mexico HM143496 HM143205 HM143691 HM143310 HM143103 HM143592 HM143406 Peterson 22101 & Saarela Mexico HM143497 HM143206 HM143690 HM143309 HM143104 HM143591 HM143407 Peterson 15838 & Valdes Reyna Peterson 6227 & Annable Peterson 16103 & Rosales Mexico HM143498 HM143207 HM143692 HM143311 HM143105 HM143593 HM143408 Mexico Mexico HM143499 HM143500 HM143208 HM143209 HM143693 HM143694 HM143312 HM143313 HM143106 HM143107 HM143594 — HM143409 HM143410 Soreng 5302, Peterson & Sun Hang Peterson 22447 & Saarela China HM143501 HM143210 HM143695 HM143314 HM143108 HM143595 HM143411 Mexico GU359627 GU359953 GU360717 GU360254 GU359115 GU360406 GU359444 Peterson 21262 & Saarela Peterson 7900 & Annable Mexico USA HM143502 HM143503 HM143211 HM143212 HM143696 HM143697 HM143315 HM143316 HM143109 HM143110 — HM143596 HM143412 HM143413 Peterson 6285 & Annable USA HM143504 HM143213 HM143698 HM143317 HM143111 HM143597 HM143414 Peterson 19817, Saarela & Sears Peterson 7832 & Annable USA GU359617 GU359978 GU360677 GU360212 GU359163 GU360431 GU359454 USA HM143505 HM143214 HM143699 HM143318 HM143112 HM143598 HM143415 Peterson 22129 & Saarela Peterson 21637, Soreng, LaTorre & Rojas Fox Peterson 22061 & Saarela Peterson 15928 & Valdes Reyna Peterson 19443, Soreng, Salariato & Panizza Peterson 14843, Blackburn & Peterson Mexico Peru GU359629 GU359616 GU359951 GU359952 GU360729 GU360718 GU360256 GU360255 GU359117 GU359116 GU360357 GU360405 GU359481 GU359380 Mexico Mexico HM143506 HM143507 HM143215 HM143216 HM143700 HM143701 HM143319 HM143320 HM143113 HM143114 HM143599 HM143600 HM143416 — Argentina GU359765 GU359950 GU360679 GU360214 GU359161 GU360404 GU359456 USA HM143508 HM143217 HM143702 HM143321 HM143115 HM143601 HM143417 Muhlenbergia purpusii Mez Muhlenbergia quadridentata (Kunth) Trin. Muhlenbergia ramosa (Hack. ex Matsum.) Makino Muhlenbergia ramulosa (Kunth) Swallen Muhlenbergia reederorum Soderstr. Muhlenbergia repens (J. Presl) Hitchc. Muhlenbergia reverchonii Vasey & Scribn. Muhlenbergia richardsonis (Trin.) Rydb. Muhlenbergia richardsonis (Trin.) Rydb. Muhlenbergia rigens (Benth.) Hitchc. Muhlenbergia rigida (Kunth) Kunth Muhlenbergia rigida (Kunth) Kunth Muhlenbergia robusta (E. Fourn.) Hitchc. Muhlenbergia schreberi J. F. Gmel. Muhlenbergia sericea (Michx.) P. M. Peterson [Vol. 97 Peterson 20861 & Saarela American Journal of Botany Muhlenbergia mexicana var. filiformis (Torr.) Scribn. Muhlenbergia mexicana (L.) Trin. Muhlenbergia microsperma (DC.) Kunth 1552 Appendix 1. Continued Taxon Muhlenbergia setifolia Vasey Muhlenbergia sinuosa Swallen Muhlenbergia sobolifera (Muhl. ex Willd.) Trin. Muhlenbergia speciosa Vasey Muhlenbergia uniflora (Muhl.) Fernald Muhlenbergia utilis (Torr.) Hitchc. Muhlenbergia vaginata Swallen Muhlenbergia versicolor Swallen Muhlenbergia villiflora var. villosa (Swallen) Morden Muhlenbergia virescens (Kunth) Trin. Muhlenbergia virescens (Kunth) Trin. Muhlenbergia virletii (E. Fourn.) Soderstr. Muhlenbergia wrightii Vasey ex J. M. Coult. Muhlenbergia x involuta Swallen Munroa argentina Griseb. Orinus kokonorica (K. S. Hao) Keng ex X. L. Yang Pereilema beyrichianum (Kunth) Hitchc. Pereilema ciliatum E. Fourn. Pereilema crinitum J. Presl Perotis hordeiformis Nees Voucher Country rps16-trnK rps3 ITS rps16 intron ndhA intron HM143509 HM143218 HM143703 HM143322 HM143116 HM143602 HM143418 Mexico — HM143219 HM143704 HM143323 HM143117 HM143603 HM143419 USA HM143510 HM143220 — HM143324 HM143118 HM143604 HM143420 Peterson 13616, Dietrich, Braxton, & Gonzalez Elizondo Mexico HM143511 HM143221 HM143705 HM143325 HM143119 HM143605 HM143421 Peterson 22362 & Saarela Peterson 15238 & Cayouette Peterson 13709 Mexico USA Mexico HM143512 HM143513 HM143514 HM143222 HM143223 HM143224 HM143706 HM143707 HM143708 HM143326 HM143327 HM143328 HM143120 HM143121 HM143122 HM143606 HM143607 HM143608 HM143422 — HM143423 Peterson 21243 & Saarela Peterson 22053 & Saarela Mexico Mexico HM143515 HM143516 HM143225 HM143226 HM143709 HM143710 HM143329 HM143330 HM143123 HM143124 HM143609 HM143610 HM143424 HM143425 Peterson 22141 & Saarela Peterson 15778 & Saarela Mexico USA HM143517 HM143518 HM143227 HM143228 HM143711 HM143712 HM143331 HM143332 HM143125 HM143126 HM143611 HM143612 — HM143426 Peterson 22344 & Saarela Mexico HM143519 HM143229 HM143713 HM143333 HM143127 HM143613 HM143427 Peterson 22016 & Saarela Peterson 5619 & Annable Mexico USA — HM143520 HM143230 HM143231 HM143714 HM143715 HM143334 HM143335 HM143128 HM143129 HM143614 HM143615 — HM143428 Peterson 19429, Soreng, Salariato & Panizza Peterson 13212, Annable, Pizzolato, Gordon, Frett, Frick, Morrone & Griner Peterson 20862 & Saarela Argentina GU359630 GU359992 GU360720 GU360266 GU359118 GU360267 — USA HM143521 HM143232 HM143716 HM143337 HM143130 HM143616 HM143429 USA GU359631 GU359994 GU360715 GU360258 GU359119 GU360275 GU359463 Peterson 5735 & Annable Peterson 22417 & Saarela Peterson 9913 & Annable Peterson 15811 & Valdes Reyna Peterson 21259 & Saarela Peterson 22412 & Saarela Peterson 9724 & Campos Villanueva Peterson 20964, Saarela, Lara Contreras & Reyna Alvarez Peterson 6284 & Annable Peterson 15505, Soreng & Judziewicz Soreng 5447, Peterson & Sun Hang Peterson 20366, Soreng & Romaschenko Peterson 20106, Hall, Alvarez Marvan & Alvarez Jimenez Peterson 22191 & Saarela Soreng 5717, Peterson & Sun Hang USA Mexico Mexico Mexico HM143522 — — HM143523 HM143233 HM143234 HM143235 HM143236 HM143717 HM143718 HM143719 HM143720 HM143338 — HM143339 HM143340 HM143131 — HM143132 HM143133 HM143617 HM143618 HM143619 HM143620 HM143430 — — HM143431 Mexico Mexico Mexico HM143524 HM143525 HM143526 HM143237 HM143238 HM143239 HM143721 HM143722 — HM143341 HM143342 HM143343 HM143135 HM143134 HM143136 HM143622 HM143621 — HM143433 HM143432 — Mexico HM143527 HM143240 HM143723 HM143344 HM143137 HM143623 HM143434 USA Chile HM143528 GU359633 HM143241 GU360006 HM143724 GU360723 HM143345 GU360260 HM143138 GU359121 HM143624 — HM143435 GU359385 China GU359628 GU359999 GU360728 GU360259 GU359140 GU360270 GU359399 Peru GU359597 GU359995 GU360712 GU360247 GU359129 GU360280 GU359493 Mexico GU359598 GU359979 GU360719 GU360246 GU359130 GU360281 GU359516 Mexico China GU359599 GU359600 GU359993 GU359991 GU360710 GU360708 GU360245 GU360243 GU359131 GU359132 GU360282 GU360283 GU359519 GU359520 1553 rpl32-trnL Mexico Peterson et al.—Phylogeny of Muhlenberginiinae Muhlenbergia spiciformis Trin. Muhlenbergia straminea Hitchc. Muhlenbergia stricta (J. Presl) Kunth Muhlenbergia subaristata Swallen Muhlenbergia tarahumara P. M. Peterson & Columbus Muhlenbergia tenella (Kunth) Trin. Muhlenbergia tenuiflora (Willd.) Britton, Sterns & Poggenb. Muhlenbergia tenuifolia (Kunth) Kunth Muhlenbergia texana Buckley Muhlenbergia thurberi (Scribn.) Rydb. Muhlenbergia torreyi (Kunth) Hitchc. ex Bush Muhlenbergia uniflora (Muhl.) Fernald ndhF Peterson 20942, Saarela, Lara Contreras & Reyna Alvarez Peterson 7976, Annable & Herrera Peterson 20834 & Saarela September 2010] Appendix 1. Continued Taxon Taxon Redfieldia flexuosa (Thurb. ex A. Gray) Vasey Schaffnerella gracilis (Benth.) Nash Schedonnardus paniculatus (Nutt.) Trel. Scleropogon brevifolius Phil. Sohnsia filifolia (E. Fourn.) Airy Shaw Sporobolus cryptandrus (Torr.) A. Gray Vaseyochloa multinervosa (Vasey) Hitchc. Willkommia sarmentosa Hack. Zoysia macrantha Desv. Country ndhF rpl32-trnL rps16-trnK rps3 ITS rps16 intron ndhA intron Peterson 7845 & Annable USA GU359604 GU359985 GU360702 GU360191 GU359138 GU360289 GU359525 Schaffner 134 Peterson 12070 & Annable Mexico USA — GU359609 GU359981 GU359936 — GU360673 — GU360170 — GU359201 — GU360375 — GU359529 Peterson 19280, Soreng, Salariado & Panizza Peterson 11129 & Annable Argentina GU359611 GU359919 GU360635 GU360167 GU359203 − GU359530 Mexico GU359612 GU359918 GU360634 GU360166 GU359204 GU360350 GU359531 Peterson 22003 & Saarela Mexico GU359674 GU359914 GU360631 GU360162 GU359208 GU360354 GU359524 Carter 2784 USA GU359669 GU359920 GU360639 GU360154 GU359217 GU360364 GU359512 FLSP 457 Seydel 448 Peru GU359675 South Africa GU359601 GU359898 GU359988 GU360616 GU360705 GU360148 GU360240 GU359224 GU359135 GU360370 GU360277 GU359503 GU359522 Peterson 15686 & Soreng Peterson 21997& Saarela Peterson 14437, Soreng & Rosenberg Swallen 10041 Chile Mexico Australia GU359681 GU359682 GU359683 GU359948 GU359947 GU359946 GU360668 GU360667 GU360666 GU360194 GU360195 GU360205 GU359172 GU359173 GU359174 GU360361 GU360321 GU360322 GU359565 GU359557 GU359550 USA GU359656 GU359925 GU360646 GU360177 GU359193 GU360342 GU359544 Schweickerdt 2181 Soreng 5913 & Peterson South Africa GU359657 Australia GU359660 GU359924 GU360017 GU360645 GU360641 GU360252 GU360020 GU359194 GU359142 GU360343 GU360346 GU359545 GU359558 American Journal of Botany Swallenia alexandrae (Swallen) Soderstr. & H. F. Decker Tragus berteronianus Schult. Trichoneura eleusinoides (Rendle) Ekman Trichoneura weberbaueri Pilg. Tridens muticus (Torr.) Nash Triodia basedowii Pritz. Voucher 1554 Appendix 1. Continued

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