THAI FOREST BULL., BOT. 47(2): 193–195. 2019. DOI https://doi.org/10.20531/tfb.2019.47.2.11 Amomum spathilabium (Zingiberaceae: Alpinieae), a new species from northern Thailand WITTAYA KAEWSRI1 & SUPANATH KANJANAWATTANAWONG1,* ABSTRACT Amomum spathilabium, a new species from Nan Province in northern Thailand, is described and illustrated. It is closely related to A. subcapitatum but differs in the labellum shape, anther crest shape and longer ligule. Details on distribution, ecology, etymology, and a preliminary conservation assessment are provided. KEYWORDS: Amomum subcapitatum, Doi Phu Kha, native plant, spathulate labellum, taxonomy. Accepted for publication: 23 September 2019. Published online: 12 November 2019 INTRODUCTION Amomum Roxb. (Zingiberaceae: Alpinieae) as currently understood consists of approximately 64 species of which almost 30 were previously recognized as Elettariopsis curtisii Baker (De Boer et al., 2018). As currently delimited, Amomum species are characterized by having radical inflorescences, bracts subtending single flowers and staminodes small triangulate or oblong, or absent, but never connate to the filament, and the fruit is winged (at least partly), or angled to grooved, (De Boer et al., 2018). The greatest diversity of Amomum is found in northeast India and the Indochinese floristic region, with several species in the Amomum maximum Roxb. alliance extending to Sundaland (Larsen, 2005). There seems to be a disjunction with no species occurring in Sulawesi and the Philippines, although a few species from the A. maximum alliance occur again in New Guinea and wet tropical Australia (northern Queensland). Our recent exploration in northern Thailand have supported the treatment of Amomum and allied genera in Alpinieae for the Flora of Thailand. One species of Amomum with a narrow white labellum and winged fruits was collected during the fieldwork by the first author between 2004–2010 in Doi Phu Kha National Park, Pua District, Nan Province. It did not match any of the species treated in the latest revisions of Amomum in Cambodia, Laos and Vietnam and 1 Flora of China. After further examination of the flowers, fruits and comparison of type material and protologues of all known species with winged fruits from other adjacent areas such as India, China, Cambodia, Laos and Vietnam (e.g. Roxburgh, 1820; Wu & Larsen, 2000; Lamxay & Newman, 2012), it is concluded that this collection represent a new species which we describe and illustrate below as Amomum spathilabium. DESCRIPTION Amomum spathilabium W.Kaewsri, sp. nov. Type: Thailand, northern: Nan, Doi Phu Kha, 19° 12.244′ N, 101° 4.948′ E, 20 June 2010, Kaewsri-254 (holotype BKF!; isotypes BK!). Fig. 1. Similar to Amomum subcapitatum Y.M.Xia by its winged fruits and and leaf blade, but differs in its ligule being longer, bilobed, 5–7 cm long, papery, apex dry at maturity, glabrous; and the glabrous petiole, 7–17 cm long; a comparison of the characters of these two species is given in Table 1. Clump–forming herb. Leafy shoots stout, 5–9 leaves, ca 3 m tall. Leaves sheath purplish green, glabrous; ligule bilobed, 5–7 cm long, papery, apex dry at maturity, glabrous; petiole 7–17 cm long; lamina oblong to lanceolate-oblong, 30–85 × 7.5–20 cm, lower surface pale green, densely white pubescent, base cuneate to obtuse, apex acute or acuminate. Mahidol University, Amnatcharoen Campus, Muang, Amnatcharoen 37000, Thailand. * Corresponding author: supanath.kan@mahidol.edu © 2019 Forest Herbarium THAI FOREST BULLETIN (BOTANY) VOL. 47 NO. 2 194 Inflorescence ovoid to broadly ovoid, 5–6 × 7–8 cm; peduncle 4–5 cm long; peduncular bract broadly ovate, ca 2 × 3 cm, papery, apex acuminate; bract broadly ovate, ca 4.5 × 3 cm, glabrous, apex obtuse, brown, soon disintegrating, subtending ca 35 flowers; bracteole absent. Calyx tubular, ca 3 cm long including ovary, apex 3-fid, shallowly split ca 1 cm on one side, outer surface sparsely pubescent, creamy white and pale brown at apex. Corolla creamy white, tube ca 3.3 cm long including ovary, dorsal lobe hooded, oblong, ca 2.5 × 1 cm, apex apiculate, lateral lobes narrower, apex blunt, hooded. Lateral staminodes subulate, ca 1 mm long. Labellum spathulate, spreading, ca 2.5 × 1.5 cm, base attenuate, apex obtuse and lateral margin slightly revolute, white with yellow blotches along mid-band, with pale red veins radiating along midband to margin, base white pubescent. Stamen creamy white, glabrous; filament ca 2 mm long; anther ca 1.2 cm long, dehiscing lengthwise, sparsely pale red dots along margins; anther crest fan-shaped, entire, spreading, ca 7 × 1.5 mm, creamy white. Ovary cylindrical, ca 8 mm long, A B 1 cm C D E F 1 cm 1 cm 1 cm 1 cm G H I Figure 1. Amomum spathilabium W.Kaewsri: A–B. Habit; C. Detail of ligules; D. Leaves; E. Inflorescences; F. Stamen; G. Detail of flower including a calyx, pistil and corolla (from left): H. Detail of labellum (from left): front and back views; I. Infructescence with mature fruits. AMOMUM SPATHILABIUM (ZINGIBERACEAE: ALPINIEAE), A NEW SPECIES FROM NORTHERN THAILAND (W. KAEWSRI & S. KANJANAWATTANAWONG) smooth, with crimson band surrounding upper half; stigma cup-shaped, aperture narrowly transverse, edge hairy; style glabrous or glabrate; stylodes blunt, ca 5 mm long. Fruit 10–30 per infructescence, ovoid, longitudinally 9-winged, 4–4.5 × 2.8–3 cm, crimson, glabrous, calyx remnant ca 2 cm long at apex, fruit stalk 0.5–1 cm long. Distribution.— Endemic to Thailand Ecology.— Growing in montane evergreen forest, on the slope of mountain, in light gaps, 1,326 m above sea level. Phenology.— Flowering and fruiting in June. 195 IUCN Conservation status. — In Thailand the species is rare and currently only known from one collection in Doi Phu Kha National Park, Nan Province. This species grows near camping area. Every year, many tourists visit this area which might impact on the species habitat by expanding the camping area. Based on currently available data we therefore provisionally assess this species as Endangered (EN B2 a,b (ii,iii), C2a(i), D) according to the IUCN Red list criteria (IUCN, 2012). Note.— Morphological differences between Amomum spathilabium and A. subcapitatum are shown in Table 1. Etymology.— The specific epithet of this new species refers to its main distinguishing character, the spathulate labellum shape. Table 1. The character differences between Amomum spathilabium and A. subcapitatum. Characters A. spathilabium A. subcapitatum ligule length 5–7 cm 1–1.4 cm labellum shape spathulate elliptic anther crest shape fan-shaped 2-lobed ACKNOWLEDGEMENTS The authors would like to thank the Royal Botanic Garden Edinburgh for supporting our work at the Herbarium of Royal Botanic Garden Edinburgh (E). A Royal Society International Travel Grant allowed Wittaya Kaewsri to visit Edinburgh. Exploration work was supported by the TRF/ BIOTEC Special Program for Biodiversity Research and Training, grant BRT R153060. We are grateful to the staff of Doi Phu Kha National Park for helping facilitate our field trip. Thanks also to Assoc. Prof. Dr Yingyong Paisooksantivatana for his kind improvements to the manuscript. REFERENCES De Boer, H., Newman, M., Poulsen, A.D., Droop, A.J., Fér, T., Hiên, L.T.T., Hlavatá, K., Lamxay, V., Richardson, J.E., Steffen, K. & LeongŠkorničková, J. (2018). Convergent morphology in Alpinieae (Zingiberaceae): Recircumscribing Amomum as a monophyletic genus. Taxon 67(1): 6–36. IUCN (2012). The IUCN red List of threatened species: version 3.1. 2nd ed. Gland, Switzerland & Cambridge, UK: IUCN. Lamxay, V. & Newman, M. (2012). A revision of Amomum (Zingiberaceae) in Cambodia, Laos and Vietnam. Edinburgh Journal of Botany 69(1): 99–206. Larsen, K. (2005). Distribution pattern and diversity centers of Zingiberaceae in SE Asia. In: I. Friis and H. Balselv (eds), Plant diversity and complexity patterns, local, regional and global dimensions. Proceedings of an international symposium. Royal Danish Academy Science and Letters. Copenhagen, pp. 219–228. Roxburgh, W. (1820). Plants of the Coromandel. Vol. 3. Bulmer & Co., London, 300 pp. Wu, T.L. & Larsen, K. (2000). Zingiberaceae. In: Z.Y. Wu and P.H. Raven (eds) Flora of China. (24). Science Press. Beijing, pp. 322–377.