Thai ForesT Bull., BoT. 44(1): 26–31. 2016.
doi: 10.20531/TFB.2016.44.1.06
© 2016 The Forest herbarium
INTRODUCTION
Haymondia A.N.Egan & B.Pan bis is a genus 
in the legume family (Fabaceae, Leguminosae) in 
South East Asia, distributed in mainly mountainous 
regions from Nepal eastward to southern Yunnan 
and the golden triangle of Myanmar and Thailand. 
Haymondia was recently segregated from the genus 
Pueraria DC. on the basis of molecular and morpho-
logical evidence (Egan & Pan, 2015; Egan et al., 
2016). De Candolle first described Pueraria in 1825, 
wherein he included only two species, P. tuberosa 
(Willd.) DC., moved from Hedysarum L. based on 
the observation that the species lacked the articulated 
pods of Hedysareae, and P. wallichii DC., named for 
Dr Nathaniel Wallich, who sent him the specimens 
from Nepal (De Candolle, 1825).
De Candolle (1825) united these two species 
based on broadly shared morphological characters, 
including the climbing, twining habit, woody, 
cylindrical stems, broad trifoliolate leaves, and 
elongated, axillary, “almost paniculate” inflorescences. 
However, the affiliation of P. wallichii to other con-
geners has been questioned by several contemporary 
botanists: Van der Maesen (1985) segregated 
P. wallichii from the main body of Pueraria species 
based on the observation that P. wallichii had 4 or 
more flowers per thickened brachyblast or node as 
The genus Haymondia A.N.Egan & B.Pan bis (Fabaceae) in Thailand
ASHLEY N. EGAN 1,* & CHRISTOPHER F. PUTTOCK1, 2
ABSTRACT
A synopsis of the genus Haymondia A.N.Egan & B.Pan bis in Thailand, comprised of a single species: H. wallichii (DC.) A.N.Egan 
& B.Pan bis, is given. The genus and species descriptions are provided, along with nomenclature, vernacular names, distributional 
data and specimens examined.
KEYWORDS: Fabaceae, Haymondia, Leguminosae, Pueraria, northern Thailand.
Published online: 15 September 2016
1 US National Herbarium (US), Department of Botany, Smithsonian Institution National Museum of Natural History, 10th and 
Constitution Ave, Washington DC, 20560, USA.
2 Email: christopher.puttock@gmail.com; puttockc@si.edu 
* Corresponding author. Email: egana@si.edu; ashegan2@gmail.com
opposed to 2 or 3 per node and basifixed as opposed 
to medifixed stipules; Lackey (1977a,b) discovered 
that P. wallichii lacked paraveinal mesophyll while 
most other congeners did not and that P. wallichii was 
distinct in containing canavanine, a non-proteinogenic 
amino acid that is lacking in most genera of subtribe 
Glycininae. Because of this, Lackey suggested that 
P. wallichii was generically, and perhaps subtribally 
or tribally misplaced. Lackey’s hypothesis was recently 
supported by molecular phylogenetic analysis of 
three DNA markers, matK, AS2, and the trnD-trnT 
intergenic spacer, placing outside subtribe Glycininae 
and outside the core Phaseoleae with strong support, 
and with loose association with Kennedinae and 
Desmodieae (Egan et al., 2016). As such, a new genus 
was named to accommodate Haymondia wallichii 
(DC.) A.N.Egan & B.Pan, the only species of the genus 
(Egan & Pan, 2015). Here, we describe Haymondia 
in Thailand.
MATERIALS AND METHODS
This study is based on observations in the field 
and on the examination of 88 collections from the 
following herbaria: A, AAU, BKF, BM, C, E, G, K, 
L, MO, P, QBG, US. All specimens cited have been 
seen by the authors, unless otherwise annotated as n.v.
The genus haymondia a.n.egan & B.Pan Bis (FaBaceae) in Thailand (a.n. egan & c.F. PuTTocK) 27
TREATMENT
Haymondia A.N.Egan & B.Pan bis, Phytotaxa 218(3): 
212. 2015. Type: Haymondia wallichii (DC.) A.N.Egan 
& B.Pan bis (based on Pueraria wallichii DC.)
Perennial scandent shrub with woody erect or 
climbing stems. Roots not tuberous. Leaves trifoliolate 
with basifixed, lanceolate stipules, caducous, leaving a 
narrowly elliptic stipule scar. Petioles terete; terminal 
leaflet broadly ovate, rhomboid-elliptic, to suborbicular, 
entire; stipels bristle-like. Inflorescences solitary, 
axillary pseudoracemes or terminal panicles, nodose 
or shortly branched, bearing 4 or more flowers per 
node, ascending or pendulous. Calyx campanulate; 
lobes 5, short and blunt with the upper two fused or 
minutely bifid. Corolla large; vexillum apex rounded, 
without callosities; sides not reflexed; center green 
spot and white rays. Stamens monadelphous, the 
vexillary stamen connate to staminal column in the 
middle, free below; stamens and style move up to touch 
vexillum in late blooming. Ovary elongate, strongly 
upcurved distally. Pods coriaceous, oblanceolate, 
glabrous; valves twisting upon dehiscence. Seeds 
orbicular, compressed.
A monotypic genus in the foothills of the 
Himalayas and golden triangle of Asia.
Etymology.— Haymondia is named after 
Welby Dean Haymond and Mildred Winona Davies 
Haymond, maternal grandparents of author Ashley 
N. Egan, who instilled and cultivated in her a love 
of nature and science.
Note.— Haymondia is characterized as a 
scandent shrub with basifixed, caducous stipules, 
solitary axillary or terminal pseudoracemes (sometime 
panicles in terminal inflorescences) that have 4 or 
more flowers per thickened brachyblast or short, 
lateral inflorescence branches. A particularly distinctive 
character state of Haymondia is the position of the 
stamens throughout flowering. At the onset of anthesis, 
the staminal column is positioned within the keel 
petals then later moves upward until the stamens 
and stigma are touching the vexillum, or nearly so, 
and fully reflexed from the wing and keel petals. 
Several other genera that share this character state 
include Apios, Mucuna, and Cochlianthus.
Haymondia wallichii (DC.) A.N.Egan & B.Pan bis, 
Phytotaxa 218(3): 212. 2015.— Pueraria wallichii 
DC., Ann. Sci. Nat. (Paris) 4: 97. 1825. Type: Nepal, 
1821, N. Wallich 5353a (holotype G!; isotypes BM 
000958610!, C 10012332!, C 10012333!, C 10012334!, 
K 001120653!). Figs. 1–2.
— Dolichos frutescens Buch.-Ham. ex D.Don in 
D.Don, Prodr. Fl. Nepal. 240. 1825. NEPAL: 
1802–1803, F. Hamilton (holotype: CAL n.v.).
— Pueraria wallichii DC. var. composita Graham 
ex Wall. ex Benth., J. Linn. Soc. Bot. London 9: 124. 
1867. Type. Myanmar, Taong Dong, N. Wallich 5570 
(holotype: K 001121317!; isotypes: BM 000958611!, 
G 00370594!, G 00370591!, K 000264070!, K 
000264071!).— Pueraria composita Graham ex 
Wall., Numer. List, Number 5570. 1831 (nom. nud.).
Plants 2–4(–7) m tall. Stems sparsely pubescent 
with adpressed hairs, glabrescent. Leaves with stipules 
4–11 × 2 mm, early caducous; petioles striate, 5–18 
cm long; terminal leaflets 8–28 × 8–26 cm; lateral 
leaflets smaller, oblique, 7–23 × 4–16 cm; apex 
acuminate, rarely obtuse; base cuneate; leaflets green 
and glabrous above, grey-green and sparsely adpressed 
pubescent below; veins conspicuous below, in ca 7 
pairs; petiolules 4–10 mm long with spreading hairs; 
stipels small, 1–3 mm long, falling with age. 
Inflorescences (4–)10–40(–55) cm long; bracts 
subtending the nodes, 2–5 mm long, caducous; 
pedicels 2–6 mm long, pubescent; bracteoles 2 per 
flower, ovate to lanceolate, 0.5–3 mm long, caducous. 
Calyx 4–6 mm long, short appressed hairs on the 
outside, the tube 3–5 mm long, the upper two lobes 
fused entirely or nearly so, other lobes obtuse, 0.5–1 
mm long. Corolla white to pink; vexillum obovate, 
(10–)16–19(–23) × 8–15(–18) mm; wing petals 
white or pink, darker than vexillum or keel petals, 
15–17 × 2–3 mm; keel petals strongly curved ventrally 
and basally fused, white to light pink, 14–18 × ca 3 
mm. Ovary finely hirsute, 8–12 mm long; style 4–6 
mm long, the last 2–3 mm strongly upcurved, glabrous; 
stigma terminal, globose. Stamens 14–15 mm long, 
the free end 1–2 mm long, upcurved, stamens and 
style move up to touch vexillum in late blooming; 
anthers dorsifixed, alternately on long and short 
filaments. Fruits leguminous pods, flattened, tan to 
medium brown, 5–8 ovules, not septate, 6–13 × 
0.8–1.2 cm, acuminate at both ends; style persistent, 
dehiscent when mature. Seeds orbicular to oblong, 
5–7 × 3–6 mm, ca 2.5 mm thick, brown or with black 
mottling; funicle broad, triangular in shape; aril 
elongate.
thai forest bulletin (botany) Vol. 44 no. 128
Figure 1. Haymondia wallichii (DC.) A.N.Egan & B.Pan bis. Inflorescence showing terminal panicle type. Illustration by Alice 
Tangerini.
Thailand.— NORTHERN: Chiang Mai [12 Nov. 
1911, Kerr 1556B (P); ibid, 540–1700 m, 8 Jan. 
1911, Kerr 1556 (E, K); Ban Kong, 700–1100 m, 
21 Dec. 1978, Bjørnland & Schumacker 553 (AAU, 
C); Ban Mae Tala Nuea, Mae Dat Subdistrict, 1350 m, 
[18°55’18’N 98°28’45”E], 10 Dec. 2007, Tanaka et 
al. HN8060 (QBG); Chiang Dao, 12 Dec. 1954, 
Suvarnakoses 976 (AAU, L); Doi Chiang Dao, 31 
Dec. [1931], Put 4436 (AAU, E); roadside to Khun 
Huai Ma Kok checkpoint, Doi Chiang Dao Wildlife 
Sanctuary, 1400 m, 25 Feb. 2003, Chamchumroom 
et al. 1914 (BKF); western part of Doi Chiang Dao, 
1270–1350 m, 29 Nov. 1984, Koyama et al. T39873 
(L); Doi Angka [Doi Inthanon], Me Ka Pak drainage, 
ca 1070 m, 26 Nov. 1926, Garrett 313 (E); Doi 
Inthanon, 1500 m, 13 Dec. 1984, Nanakorn WN1094 
(NY); Kio Mae Pan, Doi Inthanon National Park , 
900–1200 m, 29 Nov. 1996, Nanakorn et al. 7966 
(QBG); Doi Suthep, 5000 ft, 31 Oct. 1909, Kerr 878 
(K, P); ibid, 1800 ft, 15 Nov. 1910, Kerr 1556 (US); 
ibid, 1000–1700 ft, 12 Dec. 1904, Hosseus 207 (C); 
ibid, 10 Feb. 1926, Collins 1222 (US); ibid, 1150 
m, 23 Oct. 1958, Sørensen et al. 5857 (C, P); ibid, 
450 m, 26 Oct. 1958, Sørensen et al. 5914 (C, L); 
ibid, 1250 m, 29 Oct. 1958, Sørensen et al. 5972 (C, 
E); ibid, ca 500 m, Feb. 1987, Niyomdham & Kubat 
The genus haymondia a.n.egan & B.Pan Bis (FaBaceae) in Thailand (a.n. egan & c.F. PuTTocK) 29
1358 (P); ibid, below the Bhuping Royal Palace, 
near the helicopter area, 1275 m, 26 Dec. 1987, 
Maxwell 87-1633 (L); Camp Hoi Chan Kiang, Doi 
Suthep mountain range, ca 600 m, 26 Oct. 1920, 
Rock 116 (US); S of Pang Faen 5 km along road 
1252, a side-road to 118, 1000 m, [19°01’N 98°20’E], 
25 Nov. 1993, Larsen et al. 44817 (AAU); between 
Pang Kia and Mae Kha Chan, basin of the Mae Lao, 
750–900 m, 2 Jan. 1922, Rock 1620 (US); Payap, 
Doi (Mt) Buak Ha, W of Chiang Mai, ca 1575 m, 
[18°50’N 98°55’E], 30 Nov. 1965, Hennipman 3175 
(C, K, L, P); Pha Hom Pok, 1100 m, 25 Feb. 1958, 
Sørensen et al. 1659 (C); Queen Sirikit Botanic 
Garden, 700 m, 12 Nov. 1993, Nanakorn et al. 128 
Figure 2. Haymondia wallichii (DC.) A.N.Egan & B.Pan bis: A. habit; B. flowering branch of terminal panicle inflorescence; C. fruit; 
D. axillary inflorescence in bud (note the lateral branches shortened to brachyblasts). Photo credits: Ashley N. Egan [A,D; A.N. Egan 
13-0750 (US)], Bo Pan (B,C).
thai forest bulletin (botany) Vol. 44 no. 130
(QBG)]; Chiang Rai [Khun Tan Mts, 4000 ft, 22 
Nov. 1928, Smith 454 (US)]; Lamphun [Mi Li, 410 m, 
3 Nov. 1925, Winit 1521 (K); Doi Khun Dahn [Tan] 
National Park, along the trail from Yaw 2 to Yaw 3, 
1125 m, 3 Feb. 1994, Maxwell 94-188 (BKF)]; Mae 
Hong Son [western flank of Doi Inthanon, ca 1000 
m, [18°40’N 98°25’E], 6 Dec. 1969, van Beusekom 
& Phengklai 2359 (AAU, C, E, P); Kio Lom, border 
between Pai and Muang Districts, 1490 m, 16 Jan. 
1983, Koyama et al. 32566 (BKF); ibid, 16 Jan. 1983, 
Koyama et al. 32640 (BKF)]; Nan [50 km W of Nan, 
W of Ban Luang, 600 m, [18°51’N 100°21’E], 22 Nov. 
1993, Larsen et al. 44733 (AAU)]; Phayao [Doi Pha 
Dam, Ban Pang Tham, 1030 m, [19°30’30.17’’N 100° 
27’10.76’’E], 14 Dec. 2012, La-ongsri et al. 2592 
(QBG)]; Phrae [Phre, 180 m, Vanpruk 478 (K)]; 
NORTH-EASTERN: Loei [Phu Kradueng, S of Loei, 
1100 m, [16°53’N 101°53’E], 10 Nov. 1970, 
Charoenphol et al. 4850 (AAU, K, P); Phu Kradueng, 
ca 1300 m, [16°52’N 101°52’E], 27 Dec. 1971, van 
Beusekom et al. 4620 (C, K, P); Phu Kradueng 
National Park, 1200 m, 14 Nov. 1979, Shimizu 
T22661 (L)]; WESTERN: Kanchanaburi [Tapoh, 4 
Jan. 1962, Larsen 9144 (C, K); Tham Pha, 29 Dec. 
1961, Phengkhlai 344 (K, BKF)].
Distribution.— Following the base of the 
Himalayas eastwards from Nepal, Bhutan, India 
(Sikkim, Meghalaya), Bangladesh, Myanmar/Burma 
(Chin, Mon and Shan), northern Thailand, China 
(Yunnan), to northern Laos. Unconfirmed records 
from Uttarakhand (India) and Tibet/Xizang (China). 
Ecology.— Elevation 180–2000(–2300) m; 
hill sides, mountain slopes, and along rivers. A 
climber on shrubs in semi-evergreen oak, and pine-
dipterocarp forests, such as those typified by 
Dipterocarpus tuberculatus Roxb. and in opium 
fields and roadsides.
Phenology.— Flowering October–December 
(to February at lower elevations). Fruiting December– 
February.
Conservation.— Haymondia is common in 
Thailand and Myanmar throughout dry dipterocarp 
forests and occurs within or near the borders of 
several national parks, such as Doi Inthanon, Doi Khun 
Tan and Phu Kradueng. It is now less common in 
Yunnan, China through 19th century forest conversion 
to opium poppy cultivation. It is assessed here as 
Least Concern (LC) according to the criteria of 
IUCN (2001) based on frequency within its range 
and presence within protected areas.
Vernacular.— Ma paep wo (มะแปบวอ)(Northern); 
paep kwang yai (แปบกวางใหญ)่, ma paep kwang (มะแปบ
กวาง)(Chiang Mai).
Notes.— According to IPNI [accessed Jan. 28, 
2016] both Pueraria wallichii and Dolichos frutescens 
were published in January 1825, the former sometime 
during the month (Jan. 1825) and the latter in the 
last week of the month (26 Jan.-1 Feb. 1825). Van 
der Maesen (1985) placed Dolichos frutescens in 
synonymy of Pueraria wallichii and without clearer 
dates of publication, the priority of P. wallichii is 
retained. Van der Maesen (1985) erroneously listed 
the combination Neustanthus wallichii (DC.) Benth. 
as being published by Bentham (Pl. Jungh. 2: 234. 
1852), however, Bentham (1852) does not place this 
species in his genus Neustanthus, but associates it 
with Phaseoleae or perhaps Dalbergieae.
Etymology.— The epithet wallichii commemo-
rates Nathaniel Wallich (28 Jan. 1786–28 April 1854) 
who was appointed Surgeon to the Danish settlement 
at Serampore in Bengal, then later the Superintendent 
of the Calcutta Botanic Garden, India.
ACKNOWLEDGEMENTS
Thanks to staff of BKF, the Royal Thai Forest 
Department, and the Flora of Thailand Project for 
help and support in field collection efforts and speci-
men loans, particularly Voradol Chamchumroon, 
Kongkanda Chayamarit, Thaveechok Jumruschay, 
Rumrada Meeboonya, Nannapat Pattharahirantricin, 
Rachun Pooma, and Sukontip Sirimongkol, in no 
particular order. Thanks to staff of A, AAU, BKF, 
BM, C, E, G, K, L, MO, P, QBG, and US for specimen 
loans and access. Egan was supported in part by 
funding from East Carolina University, Smithsonian 
Institution, and the United States National Science 
Foundation (NSF DEB 1120186/1352217). 
REFERENCES
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in Pueraria (Leguminosae, Papilionoideae): The 
creation of two new genera, Haymondia and 
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________. (1977b). A synopsis of Phaseoleae 
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