A peer-reviewed open-access journal
PhytoKeys 138: 187–201 (2020)
Two new species and five new records described and illustrated for flora of Laos
doi: 10.3897/phytokeys.138.46718
RESEARCH ARTICLE
http://phytokeys.pensoft.net
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An updated checklist of Begonia (Begoniaceae) in Laos,
with two new species and five new records
Hong-Bo Ding1,2*, Mya Bhone Maw1,3*, Bin Yang1,2,
Somsanith Bouamanivong4, Yun-Hong Tan1,2
1 Southeast Asia Biodiversity Research Institute & Center for Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China 2 Center
of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Menglun, Mengla,Yunnan
666303, China 3 University of Chinese Academy of Sciences, Shijingshan District, Beijing 100049, China
4 Ecology Division, Biotechnology and Ecology Institute, Ministry of Science and Technology, P.O. Box: 2279,
Vientiane Capital, Lao PDR
Corresponding author: Yun-Hong Tan (tyh@xtbg.org.cn)
Academic editor: Xiao-Hua Jin | Received 11 October 2019 | Accepted 8 November 2019 | Published 10 January 2020
Citation: Ding H-B, Maw MB, Yang B, Bouamanivong S, Tan Y-H (2020) An updated checklist of Begonia (Begoniaceae)
in Laos, with two new species and five new records. In: Jin X-H, Xia N-H, Tan Y-H (Eds) Plant diversity of Southeast
Asia-II. PhytoKeys 138: 187–201. https://doi.org/10.3897/phytokeys.138.46718
Abstract
Two new species of Begonia L. (Begoniaceae), B. laotica (sect. Parvibegonia) and B. hypoleuca (sect. Reichenheimia), from north Laos are described and illustrated. Begonia augustinei, B. dryadis, B. lancangensis,
B. sizemoreae and B. sillentensis subsp. mengyangensis were newly recorded taxa in Laos. Furthermore, an
updated checklist of Begonia of Laos is also compiled.
Keywords
sect. Parvibegonia, sect. Reichenheimia, taxonomy, new records
Introduction
Begonia Linnaeus (1753: 1056) is the sixth largest genera of angiosperms and the number of accepted species of Begonia currently stands at 1947 (Hughes et al. 2015) and is
likely to rise to well over 2000 (Moonlight et al. 2018; Tian et al. 2018). According to
* Contributed equally as the first authors.
Copyright Hong-Bo Ding et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC
BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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the annotated checklist of south east Asia Begonia by Hughes (2008) and recent taxonomic publications (Hughes 2007; Newman et al. 2007; De Wilde et al. 2011; Averyanov and Nguyen 2012; Souvannakhoummane et al. 2016, 2018; Yang et al. 2018;
Averyanov et al. 2019), 19 species of Begonia have been described from Laos, so far.
As part of the botanical inventory of China-Laos transboundary biodiversity conservation, we carried out floristic surveys in the Phou Hin Phee National Biodiversity Conservation Area, Oudomxay Province, the Nam Ha National Biodiversity Conservation Area in
Luang Namtha Province and the Phou Dean Din National Bio-Diversity Park, Phongsaly
Province of northern Laos. During the fieldwork from 2018 to 2019, some interesting species of Begonia have been collected. After reviewing the literature and herbarium specimens,
we described and illustrated two species as new to science and five species as new records for
the flora of Laos. We provided an updated total of 26 species for the Begonia flora of Laos.
Begonia laotica is classified under B. sect. Parvibegonia A. de Candolle (1859: 136)
according to its small and tuberous habitat, axile placentation, 2-locular ovary, 2 styles
and fruit with 3 unequal wings (Doorenbos et al. 1998; Moonlight et al. 2018). Begonia hypoleuca belongs to B. sect. Reichenheimia (Klotzsch, 1855: 174) A. de Candolle
(1864: 385), based on the morphological characteristics, including 2 tepals in male
flowers, axile and entire placentation, 3-locular ovary, 3 styles and fruit with 3 wings
(Doorenbos et al. 1998; Moonlight et al. 2018).
Material and methods
Measurements and morphological character assessments of the new species have been
examined, based on fresh materials and dried specimens. They have been compared
with morphologically similar species by affinities inferred using descriptions (Ku et
al. 2007; Camfield and Hughes 2018) and type specimens in herbaria (BM, E, K, B,
KUN, P, HITBC, YUNU, LE and FOF). Protologues and images of type specimens
were gathered from JSTOR Global Plants (http://plants.jstor.org).
Taxonomic treatments
Begonia laotica Y.H.Tan & H.B.Ding, sp. nov.
urn:lsid:ipni.org:names:77204211-1
Figure 1
sect. Parvibegonia A. de Candolle
Diagnosis. The new species is mostly similar to B. josephii A. de Candolle (1859: 126)
in its peltate, stemless, tuberous habit, but significantly differs by fleshy reddish bristles
at the petiole apex (vs. without), ovary 2-locular (vs. 3-locular) and styles 2 (vs. 3).
Two new species and five new records described and illustrated for flora of Laos
189
Figure 1. Begonia laotica Y.H.Tan & H.B.Ding, sp. nov. A habitat B leaf blade adaxially C leaf blade
abaxially (showing fleshy reddish bristles at the petiole apex) D flowers (front view) E flowers (lateral view)
F inflorescence G mature fruits H habit I staminate flower J pistillate flower (young) K stamens (lateral
view) L stamens (front view) M cross section of ovary. Photographed by H.B. Ding.
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Type. Laos. Oudomxay Province, Maung Xai, Phou Hin Phee National Biodiversity Conservation Area, 20°43'18.69"N, 102°08'47.97"E. 1378 m elev., 25 October
2018, flowering, Y.H. Tan & H.B. Ding L0827 (holotype: HITBC!; isotypes: HNL!).
Description. Monoecious herb, stemless, tuberous, 18−25 cm high, tuber small,
subglobose, 12−15 mm in diameter. Stipule: broadly lanceolate, 2−3 mm long,
membranous, sparsely glandular hairy, margin fringed by hairs, deciduous. Leaf:
petiole 6−15 cm long, glabrous or sparsely puberulous; blade ovate, nearly symmetric, 9.2−13.5 × 5.8−11 cm, peltate, base rounded, apex acuminate, margin slightly
denticulate, with sparse short hairs, upper surface green, glabrous, lower surface paler, venation palmate-pinnate, tomentose on the veins, fleshy reddish bristles at the
petiole apex, thinly succulent in life, thinly papery when dried. Inflorescence: axillary, terminal cyme; peduncle puberulent, 7.2−10.9 cm long, branching 2−3 times;
bracts narrowly ovate, ca. 4.0 × 2.5 mm, membranous, reddish line along the middle,
slightly glandular hairy, margin fringed by glandular hairs. Staminate flower: pedicel
1.1−1.8 cm, membranous, covered with glandular hairs, tepals 4, pink, unequal, outer
2, ovate, 10−13 × 7−17 mm, glandular hairs on the outer surface, margin entire, inner
2, elliptic, 7−10 × 2−4 mm, glabrous, margin entire; stamens 15−20, anther obovate,
ca. 1 mm. Pistillate flower (young): pedicel 0.9−1.2 cm long, membranous, glandular
hairy, tepals 5, pink, unequal, outer 2, ovate, 4−6 × 3−4 mm, inner 2, elliptic, 3−5
× 1−3 mm, glandular hairs on the outer surface, especially at the base; ovary 2-locular,
placentae axial, placentae 2 per locule, styles 2, stigmas bifid with twisted bands, highly
convolute, golden yellow. Capsule nodding, obovate, pinkish tomentose, unequally
3-winged, abaxial wing oblong, ca. 13 mm long, lateral wings shorter, ca. 3 mm long.
Phenology. Flowering in October–November and fruiting in December.
Distribution. Endemic to the type locality, Oudomxay Province, Maung Xai,
Phou Hin Phee National Biodiversity Conservation Area, Laos.
Ecology. Restricted to the shaded base of limestone cliff at ca. 1378 m elevation.
Etymology. The specific epithet ‘laotica’ refers to the type locality in Laos.
Conservation status. Data Deficient (DD) (IUCN 2017). The new species was
only collected from the limestone cliff of Hin Phee National Biodiversity Conservation
Area. Due to its remote habitat, we suggested that the species may not suffer from strong
human disturbance. According to the available information, we proposed the preliminary conservation status of this new species as Data Deficient (DD) (IUCN 2017).
Notes. Begonia laotica is phenotypically most similar to B. josephii in its tuberous
habit, ovate and peltate leaves, but it can easily be distinguished by its glabrous upper
leaf surface (vs. hispid all over), fleshy reddish bristles at the petiole apex (vs. without),
bracts narrowly ovate and fringed by glandular hairs (vs. lanceolate and glabrous), male
flowers pedicels with glandular hair (vs. glabrous), outer tepals ovate (vs. broadly obovate), inner tepals elliptic (vs. spathulate), anther obovate (vs. ellipsoid), female flowers
pedicels with sparsely glandular hair (vs. glabrous), glandular hair on the outer surface
(vs. glabrous), ovary 2-locular (vs. 3-locular) and styles 2 (vs. 3). This new species also
shares similar characteristics with B. subperfoliata Parish ex Kurz (1873: 81) in tuberous habit and peltate leaves, but it can easily be distinguished by its ovary 2-locular (vs.
3-locular) and styles 2 (vs. 3).
Two new species and five new records described and illustrated for flora of Laos
191
Begonia hypoleuca Y.H.Tan & H.B.Ding, sp. nov.
urn:lsid:ipni.org:names:77204213-1
Figure 2
sect. Reichenheimia (Klotzsch) A. de Candolle
Diagnosis. The new species is mostly similar to B. henryi Hemsley (1887: 322), but
differs by its glabrous leaves, petiole with linear red dots and pubescent, slightly denticulate leaf margin and fewer stamens.
Type. Laos. Luang Namtha Province, Nam Ha National Biodiversity Conservation Area, Nam O. Village, 20°04'48.16"N, 101°06'58.46"E. 656 m elev., 24 October
2018, Y.H. Tan, B. Yang, H.B. Ding & X.D. Zeng L0792 (holotype: HITBC!).
Description. Monoecious herb, stemless, tuber small, globose with fibrous roots,
10−13 mm in diameter. Stipule: caducous. Leaf: petiole 7−10 cm long, succulent,
with reddish linear dots, sparsely pubescent or subglabrous. Blade slightly triangular
ovate or broadly ovate, 6−12 × 5−8.5 cm, base cordate, apex acuminate, margin slightly
denticulate, upper surface green, lower surface paler or silver, glabrous, venation palmate-pinnate, midrib pale green, lateral veins 4−6 pairs. Inflorescence axillary, cymose,
peduncle ca. 6 cm long, reddish, glabrous, branching 2−4 times, 2−6 male flowers, ca.
2 pistillate flowers, bracts caducous, ca. 2 × 1 mm. Staminate flower: pedicel 1.0−1.2
cm long, membranous, reddish at the basal part and pink, glabrous, tepals 2, pink,
margin entire, glabrous on both surfaces, broadly ovate, 12 × 10 mm, apex acute, base
rounded; stamens 10−15, filaments 1.5−2 mm long, anthers 1−1.5 mm, ellipsoid, yellow. Pistillate flower: pedicle ca. 1.8 cm long, reddish to pink, tepals unknown, ovary
3-locular, placentae axial, entire, styles 3. Capsule pale green, nodding, ellipsoid, dorsal wing enlarged, 7−10 mm long, two lateral wings, smaller, 2−3 mm long.
Phenology. Flowering and fruiting in October–November.
Distribution. The species is known only from the type locality, Luang Namtha
Province, Nam Ha National Biodiversity Conservation Area, Laos.
Ecology. The species was collected on shaded moist limestone rock surfaces of
stone forest at 656 m elevation.
Etymology. The specific epithet ‘hypoleuca’ refers to the lower surface of its paler
or silver leaf.
Conservation status. Data Deficient (DD). Begonia hypoleuca has been collected
on only one occasion from the type locality. However, the type locality is located in the
Nam Ha National Biodiversity Conservation Area and we did not discover any strong
pressure on the species. Thus, the species preliminarily has been assigned in the Data
Deficient (DD) category as being appropriate according to the guidelines for using the
IUCN Red List Categories and Criteria (IUCN 2017).
Notes. Begonia hypoleuca is most similar in morphological characteristics to B. henryi
Hemsl. under the section Reichenheimia. It can, however, be distinguished by the following
characteristics, including reddish linear red dots on petiole (vs. without), sparsely pubescent
on petiole (vs. brown villous), slightly denticulate leaf margin (vs. crenate), glabrous leaves
(vs. pubescent), leaf upper surface green (vs. green with dark green patches), lower surface
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Figure 2. Begonia hypoleuca Y.H.Tan & H.B.Ding, sp. nov. A habitat B flowers (front view) C flowers
(lateral view) D habit E inflorescence F leaves G tepals of staminate flower (back view) H stamens with
peduncle I tepals of staminate flower (front view) J mature fruit with peduncle K mature fruit L–N serial
cross sections of ovary. Photographed by H.B. Ding.
Two new species and five new records described and illustrated for flora of Laos
193
pale green (vs. pale green with reddish patches), male flower tepals broadly ovate (vs. oblateorbicular), apex acute (vs. rounded), stamens number fewer 10–15 (vs. up to 30).
New records for Laos
Begonia augustinei Hemsley
Figure 3 A–E
Begonia augustinei Hemsley, Gard. Chron 3 (28): 286. 1900; T.C. Ku in T.L. Wu (ed.),
Fl. Reipubl. Popularis Sin. 52(1): 256. 1999; S.H. Huang & Y.M. Shui in C.Y. Wu
(ed.), Fl Yunnan. 12: 213. 2006; T.C. Ku et al. in C.Y. Wu & P.H. Raven (eds), Fl.
China 13: 163. 2007. Type: China, Yunnan Province, Simao, A. Henry 12333A
(holotype: B100365120!).
Specimens examined. Laos. Luang Namtha Province, Nam Ha National Biodiversity Conservation Area, Near Nalan Neua Village, 20°49'54.92"N, 101°19'24.85"E.
646 m elev., 13 October 2018, Y.H. Tan, B. Yang, H.B. Ding & X.D. Zeng L0687
(HITBC; HNL); Oudomxay Province, Maung Xai, Phou Hin Phee National Biodiversity Conservation Area, 20°43'30.86"N, 102°08'42.39"E. 1288 m elev.,
25 October 2018, Y.H. Tan & H.B. Ding L0819 (HITBC; HNL); Oudomxay
Province, Maung Xai, Phou Hin Phee National Biodiversity Conservation Area,
20°43'23.74"N, 102°08'42.84"E. 1224 m elev., 25 October 2018, Y.H. Tan & H.B.
Ding L0822 (HITBC).
Distribution. China, Laos.
Note. This species is characterised by elongate rhizomes, extremely asymmetric
leaves, base cordate to deeply cordate, margin irregularly serrulate (Hemsley 1900; Ku
1999; Huang and Shui 2006; Ku et al. 2007).
Begonia dryadis Irmscher
Figure 3 F–K
Begonia dryadis Irmscher, Not. Bot. Gard. Edinb. 21(1): 41. 1951; T.C. Ku in T.L. Wu
(ed.), Fl. Reipubl. Popularis Sin. 52(1): 246. 1999; S.H. Huang & Y.M. Shui in
C.Y. Wu (ed.), Fl Yunnan. 12: 215. 2006; T.C. Ku et al. in C.Y. Wu & P.H. Raven
(eds), Fl. China 13: 171. 2007. Type: China, Yunnan Province, Kuen-ger, Che-li
Hsien, 1100 m elev., October 1936, C.W. Wang 79349 (holotype: KUN0370809).
Specimens examined. Laos. Oudomxay Province, Maung Xai, Phou Hin Phee National Biodiversity Conservation Area, 20°43'18.52"N, 102°08'47.16"E. 1368 m elev.,
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Figure 3. A–E Begonia augustinei Hemsley: A habitat B staminate flowers (front view) C leaf blade
(adaxially and abaxially) D pistillate flowers E cross section of ovary F–K Begonia dryadis Irmscher: F habitat G staminate flowers (front view) H pistillate flower (front view) I pistillate flower (lateral view) J fruit
K cross section of ovary. Photographed by H.B. Ding.
Two new species and five new records described and illustrated for flora of Laos
195
30 March 2018, Y.H. Tan, B. Yang, H.B. Ding & X.D. Zeng L0356 (HITBC; HNL);
Oudomxay Province, Maung Xai, Phou Hin Phee National Biodiversity Conservation
Area, 20°43'18.74"N, 102°08'47.84"E. 1364 m elev., 25 October 2018, Y.H. Tan &
H.B. Ding L0815 (HITBC).
Distribution. Chian, Laos.
Note. This species was first discovered and reported in the forest understorey, by
streams in a valley of South Yunnan, China. The discovery of this species in Laos shows
the geographical linkage between two type localities. The species is differentiated from
the allied species by its short, stout rhizome and the presence of cauline leaves. (Irmscher 1951; Ku 1999; Huang and Shui 2006; Ku et al. 2007).
Begonia lancangensis S.H. Huang
Figure 4 A–C
Begonia lancangensis S.H. Huang, Acta Bot. Yunnan. 21(1): 13. 1999; S.H. Huang &
Y.M. Shui in C.Y. Wu (ed.), Fl Yunnan. 12: 230. 2006; T.C. Ku et al. in C.Y. Wu &
P.H. Raven (eds), Fl. China 13: 181. 2007. Type: China, Yunnan Province, Lancang
Xian, Fazhan He, 1600 m elev., 1995, Huang Suhua 95001 (holotype: YUNU).
Specimens examined. Laos. Luang Namtha Province, Nam Ha National Biodiversity
Conservation Area, Near Na Lun Village, 20°50'39.62"N, 101°19'41.46"E. 687 m
elev., 23 March 2018, Y.H. Tan, B. Yang, H.B. Ding & X.D. Zeng L0055 (HITBC).
Distribution. China, Laos.
Note. The species is characterised by its dioecious and erect stems with ovate or
ovate-oblong leaves and fleshy berry-like fruits (Shui and Huang 1999, Ku et al. 2007).
Additionally, B. handelii Irmscher (Irmscher 1921: 24) and B. acetosella Craib (Craib
1912: 153) have been discovered in the same locality. We suspect that this species may
be a natural hybrid species of them.
Begonia sizemoreae Kiew
Figure 4 D–F
Begonia sizemoreae Kiew, in Gard. Bull. Singapore 56: 95. 2004; Kiew R. in Adansonia
sér. 3, 29(2): 234. 2007. Type: Vietnam, Ba Vi National Park, Ha Tay Province,
ca. 80 km west of Hanoi, Accession No. 20020399 cult. in Singapore Botanic Gardens ex Palm Hammock Orchid Estate, Miami, U.S.A. R. Kiew 5304 (holotype:
SING, isotype: HN).
Specimens examined. Laos. Phongsaly Province, Phou Dean Din National Bio-Diversity Park, 21°46'02.39"N, 102°31'28.58"E. 1111 m elev., 8 April 2018, Y.H. Tan,
B. Yang, H.B. Ding & X.D. Zeng L0559 (HITBC).
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Figure 4. A–C Begonia lancangensis S.H. Huang: A habitat B staminate flower (front view) C staminate flower (back view) D–F Begonia sizemoreae Kiew: D habitat E staminate flower F pistillate flower
G–I Begonia silletensis (A. DC.) C.B. Clarke subsp. mengyangensis M.C. Tebbitt & K.-Y. Guan: G habitat
H inflorescence I staminate flower (front view). Photographed by H.B. Ding and Y.H. Tan.
Two new species and five new records described and illustrated for flora of Laos
197
Distribution. Vietnam, Laos.
Note. Begonia sizemoreae was originally described in north Vietnam. Now, its distribution in Laos has been confirmed. This species is very similar to B. rex Putz. (Putzey
1857: 141) from Assam, India, in its leaf shape, fine variegated leaves and flower structure, but it is distinct in its leaf margin with very hairy upper surface of the lamina with
hairs 5–10 mm long and its conspicuous deep crimson tertiary venation in the centre
and outer part of the lower leaf surface (Kiew 2004, 2007).
Begonia silletensis subsp. mengyangensis M.C. Tebbitt & K.Y. Guan
Figure 4 G–I
Begonia silletensis (A. DC.) C.B. Clarke subsp. mengyangensis M.C. Tebbitt & K.-Y.
Guan, Novon 12(1): 134. 2002; T.C. Ku et al. in C.Y. Wu & P.H. Raven (eds),
Fl. China 13: 198. 2007. Type: China, Yunnan Province, Xishuangbanna, on the
way from Puwen to Mengyang, at the bottom of valley in a wet area on the slope
facing N, dense forest, 21 April 1957, Sino-Soviet Union expedition 9633 (holotype
KUN0533687!).
Specimens examined. Laos. Luang Namtha Province, Nam Ha National Biodiversity
Conservation Area, Near Na Lun Village, 20°50'34.97"N, 101°20'05.69"E. 632 m elev.,
23 March 2018, Y.H. Tan, B. Yang, H.B. Ding & X.D. Zeng L0095 (HITBC; HNL).
Distribution. India, China, Bangladesh, Myanmar and Laos.
Note. The species is characterised by its dioecious and prostrate stems with large
broad leaves and fleshy berry-like fruits (Tebbitt and Guan 2002; Ku et al. 2007).
An updated checklist of Begonia species in Laos
Begonia sect. Diploclinium
Begonia adscendens C.B. Clarke
Laos: Champasak: J.K. Munzinger 250 (L, P).
Begonia hinnamnoensis Souvann & Lanors
Laos: Khammouan: Lamxay et al. HNN227 (holotype HNL, isotypes FOF, E, SING).
Begonia khammouanensis Souvann. & Lamxay
Laos: Khammouan: Lamxay et al. HNN138 (holotype HNL, isotypes FOF, E, SING).
Begonia modestiflora Kurz
Laos: Bassac: Maxwell 97-1081 (L); Me-Kong: C. Threl 2239 (BM, P).
Begonia tatianae Aver.
Laos: Khammouan: L. Averyanov, AL 820b.1 (holotype LE01049623), L. Averyanov
et al. AL820b (paratype LE01049002).
Begonia viscosa Aver. et H.Q. Nguyen
Laos: Vientiane: L. Averyanov, P.V. The, CPC2438 (holotype LE, isotype CPC).
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Begonia sect. Jackia
Begonia cladotricha M.Hughes
Laos: Khammouan: M.F. Newman et al. LAO985 (holotype E).
Begonia sect. Parvibegonia
Begonia integrifolia Dalzell
Laos: Champasak: J.F. Maxwell 97-1150 (CMU, L), C. Thorel 2226 (P[2]); C. Thorel
2226A(P[2]).
Begonia laotica Y.H. Tan & H.B. Ding
Laos: Oudomxay: Y.H. Tan, H.B. Ding L0827 (holotype HITBC!, isotypes HNL!).
Begonia namkadingensis C.-J. Yang, Souladeth & Tagane
Laos: Bolikhamxay: Tagane S. et al. L1202 (holotype FOF, isotypes HAST, HNL,
KYO), Tagane S. et al. L960 (FOF, KYO, TAI).
Begonia procridifolia Wall. ex A.DC.
Laos: A.F.G. Kerr 21188 (K, P).
Begonia sect. Petermannia
Begonia lamxayiana Souvann
Laos: Bolikhamxay: V. Lamxay et al. VL2198 (holotype HNL).
Begonia sect. Platycentrum
Begonia acetosella Craib
Laos: E. Poilane 20721 (P); Luang Namtha: Tan et al. L0050 (HITBC!, HNL!), Tan
et al. L0083 (HITBC!); Oudomxay: Tan et al. L0202 (HITBC!, HNL!).
Begonia augustinei Hemsl
Laos: Luang Namtha: Tan et al. L0687 (HITBC; HNL); Oudomxay: Tan et al.
L0819 (HITBC; HNL), Tan et al. L0822 (HITBC).
Begonia dryadis Irmsch
Laos: Oudomxay: Tan et al. L0356 (HITBC; HNL), Tan et al. L0815 (HITBC).
Begonia handelii var. handelii Irmsch.
Laos: Luang Namtha: L.J. Ahnby 129 (E), Tan et al. L0061 (HITBC; HNL); Phongsaly: Tan et al. L0502 (HITBC).
Begonia handelii var. prostrata (Irmsch.) Tebbitt
Laos: Xiangkhoang: A.F.G. Kerr 21772 (K).
Begonia lancangensis S.H. Huang
Laos: Luang Namtha: Tan et al. L0055 (HITBC).
Begonia palmata D. Don
Laos: Houaphan: E. Poilane 1938 (P), E. Poilane 2002 (P); Khammouan: M.F. Newman LAO1429 (E); Xiangkhoang: J. Delacour (P).
Begonia quadripetiolata Aver. et H. Q. Nguyen
Laos: Vientiane: L. Averyanov et al. LA-VN1510/1 (holotype LE01049395, isotype
LE01049479).
Begonia sizemoreae Kiew
Laos: Phongsaly: Tan et al. L0559 (HITBC).
Two new species and five new records described and illustrated for flora of Laos
199
Begonia siamensis Gagnep.
Laos: Attapu: F.J. Harmand 1387 (P); Phongsaly: Tan et al. L0476 (HITBC; HNL),
Tan et al. L0416 (HITBC).
Begonia silletensis subsp. mengyangensis M.C. Tebbitt & K.Y. Guan
Laos: Luang Namtha: Tan et al. L0095 (HITBC; HNL).
Begonia sect. Reichengeimia
Begonia hymenophylla Gagnep.
Laos: Champasak: C. Thorel 2358 (P), C. Thorel 2958 (P).
Begonia hypoleuca Y.H. Tan & H.B. Ding
Laos: Luang Namtha: Tan et al. L0792 (holotype HITBC!).
Begonis sect. Tetraphila
Begonia afromigrata J.J. de Wilde
Laos: Muang Awn: Kerr 20938 (BM, K, L); Vientiane: Rodda, Simonsson MR106
(TO), Rodda, Simonsson MR107 (FI).
Acknowledgements
The authors are grateful to the Biotechnology and Ecology Institute (BEI) of Lao PDR
for permission to conduct this study in Northern Lao PDR and for their support and
collaboration. We are grateful to Dr. Liang Song, Dr. Hua-Zheng Lu, Dr. Su Li, Mr.
Ren Li and Mr. Xiao-Dong Zeng for their kind help in the field. This work was financially supported by a project of the Lancang-Mekong Cooperation (LMC) Special
Fund (Biodiversity Monitoring and Network Construction along Lancang-Mekong
River Basin project) and the CAS 135 programme (No. 2017XTBG-F03), CAS “the
Belt and Road” Master Fellowship Program and CAS President’s International Fellowship Initiative (PIFI) and the project of the Southeast Asia biodiversity research
institute, Chinese Academy of Sciences (Y4ZK111B01).
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