Haymondia wallichii (de Candolle) Egan, Ashley N. & Pan, Bo, 2015

Egan, Ashley N. & Pan, Bo, 2015, Resolution of polyphyly in Pueraria (Leguminosae, Papilionoideae): The creation of two new genera, Haymondia and Toxicopueraria, the resurrection of Neustanthus, and a new combination in Teyleria, Phytotaxa 218 (3), pp. 201-226 : 212-213

Haymondia wallichii (de Candolle) A.N.Egan & B.Pan, comb. nov.

TYPE: — NEPAL. 1821, Wallich 5353a (holotype: G!; isotypes: BM[barcode BM000958610!], C[barcodes C 10012332!, C 10012333!, C 10012334!], K[barcode K001120653!]) .

Basionym: — Pueraria wallichii de Candolle, Ann. Sci. Nat. (Paris) 4: 97. 1825.

Selected Synonyms:— Pueraria composita Graham ex Wallich nom. nud., Cat. Herb. Ind. no. 5570, based on Burma, Taong Dong, Wallich 5570. Neustanthus wallichii (de Candolle) Bentham , in Miquel, Pl. Jungh. 2: 234. 1852. Pueraria wallichii de Candolle var. composita (Graham ex Wallich) Bentham, J. Linn. Soc. Bot. London 9: 124. 1867 (holotype: K[barcode K001121317!]; isotypes: BM[barcode BM000958611!], G[barcodes G00370594!, G00370591!], K[barcodes K000264070!, K000264071!]). Dolichos frutescens Hamilton , in Don, Prodr. 240. 1825.

Images: —Illustration: Figure 5 ; Photo Plate: Figure 6 .

Diagnosis: —Scandent shrub, erect, or climbing when in shade or associated with other trees or shrubs. Roots not tuberous. Leaves pinnately trifoliolate. Stipules basifixed, lanceolate and caducous. Stipels bristle-like. Pseudoracemes or panicles with many flowers on short branches, ascending or pendulous. Calyx campanulate, lobes 5, the upper two fused, short and blunt or minutely bifid. Corolla large. Vexillum apex rounded, without callosities, sides not reflexed, green spot and white rays in the center. Vexillary stamen connate to the staminal column. Staminal column moves up to touch vexillum in late blooming. Fruits coriaceous, glabrous, valves twisting upon dehiscence. Seeds orbicular and compressed.

Description: —Perennial scandent shrub, erect or climbing. Stems woody, up to 7 cm in diameter, 2–4(–7) m tall, sparsely pubescent with adpressed hairs, glabrescent with age. Stipules basifixed, linear-acuminate, 4–11 mm × 2 mm, quickly caducous, stipule scar narrowly elliptic. Leaves pinnately trifoliolate; petiole striate, 5–18 cm long; terminal leaflets broadly ovate, rhomboid-elliptic, to suborbicular, 8–28 cm × 8–26 cm, lateral leaflets smaller, oblique, 7–23 cm × 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, bristle-like, falling with age. Inflorescences solitary, axillary or terminal pseudoracemes, branched or not, (4–)10–40(–55) cm long, nodose (with brachyblasts) to short branched, 4 or more flowers per node; bracts subtending the nodes, 2–5 mm long, caducous; pedicels 2–6 mm, 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, 5-lobed, the upper two lobes fused entirely or nearly so, other lobes obtuse, 0.5–1 mm long. Corolla white to pink; vexillum obovate, green spot and white rays in the center, (10–)16–19(–23) mm × 8–15(–18) mm, apex rounded, auricles not reflexed, without callosities at base; wing petals white or pink, darker than vexillum or keel petals, 15–17 mm × 2–3 mm; keel petals strongly curved, ventrally and basally fused, white to light pink, 14–18 mm × 3 mm. Ovary elongate, finely hirsute, 8–12 mm long; style 4–6 mm long, the last 2–3 mm strongly upcurved, glabrous, stigma terminal, globose. Stamens monadelphous, the vexillary stamen connate to staminal column in the middle, free below, 14–15 mm long, the free end 1–2 mm, upcurved, stamens and style move up to touch vexillum in late blooming; anthers dorsifixed, alternately on long and short filaments. Fruits leguminous pods, flattened, oblanceolate, tan to medium brown, glabrous, coriaceous, ca. 5–8 ovuled, not septate, 6–13 cm × 0.8–1.2 cm, acuminate at both ends, style persistent, dehiscent when mature, valves twisting. Seeds orbicular to oblong, ca. 5–7 mm × 3–6 mm, ca. 2.5 mm thick, compressed, brown or with black mottling; funicle broad, triangular in shape; aril elongate.

Phenology: —Flowering July to October (to February at lower elevations). Fruiting October to February.

Distribution and Ecology: — Bangladesh, Bhutan, China (Tibet, Yunnan), India (E Himalayas, Meghalaya), Myanmar, Nepal, Thailand. Elevation 180–2000 (–2300) m; in hills and forest margins of dry evergreen forests where it is often associated with Dipterocarpaceae , particularly Shorea robusta , or with Quercus ; in open grassy vegetation, on slopes, along rivers.

Conservation: — Haymondia is fairly common in Thailand and Burma throughout dry dipterocarp forests and occurs within or near the borders of several national parks. It is less common in China and areas at the edge of its range. 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.

Etymology: —This genus is named after Welby Dean Haymond and Mildred Winona Davies Haymond, maternal grandparents of author Ashley N. Egan, who instilled and cultivated a love of nature and science in her by the simple act of allowance.

Vernacular:—ẾËƀ xu mi ge (Chinese), บะแปบวอ ma paep wo (Thai)

Discussion: — Haymondia wallichii , which commemorates Dr. Wallich who sent it, along with a number of other plant specimens, to de Candolle from Nepal (its type locality), was originally described by de Candolle in 1825 along with Pueraria tuberosa (the type species for Pueraria ). The two species resemble each other superficially, both having large trifoliolate leaves, twining habit, and long, pendulous inflorescences. However, careful examination confirms that the two species are strikingly different. Lackey (1977b) tentatively separated members of genus Pueraria into four groups based on morphological differences such as number of flowers per node, stipule type, calyx type, callosities on the vexillum, and fruit type, with P. wallichii , P. peduncularis , and P. stracheyi comprising his group D. Lackey’s (1977b) group D admittedly comprised those species which he felt were “surely anomalous in the genus but fits nowhere else.” Lackey also found that P. wallichii contains the free amino acid canavanine, a chemical that most species of subtribe Glycininae lack. In fact, Lackey (1977b) went so far as to suggest that P. wallichii was not only anomalous in the genus, but perhaps in the tribe as well: “all Pueraria species studied have paraveinal mesophyll, except for P. peduncularis and P. wallichii . This substantiates the morphological data which indicates that these two species are probably generically, and perhaps subtribally or tribally misplaced”. Van der Maesen (1985) revised the genus Pueraria into three sections: Pueraria, Schizophyllon, and Breviramulae , placing wallichii into the latter, a motley group including the two new genera presented here. In spite of their observations, neither Lackey nor van der Maesen took action to describe new genera for or move the anomalous species, largely due to uncertainty as to true relationships. Lee and Hymowitz (2001) were the first to substantiate the hypotheses of these authors using phylogenetic evidence. Their rps16 phylogeny included P. pulcherrima , P. phaseoloides , P. lobata , P. stricta , and P. wallichii . Their findings support the exclusion of P. wallichii from Pueraria s.s., but they, also, did not take revisionary action, suggesting that “more taxa of Pueraria that represent all four groups should be included in a rigorous molecular investigation.” Cagle (2013) and Egan et al. (in prep.) included a comprehensive sampling of Pueraria as well as many other genera to ascertain how these anomalous species were related to other phaseoloid genera and found that Haymondia is a distinct phylogenetic lineage at the base of tribe Phaseoleae , but found no clear affinity of Haymondia for any other genera. A key feature of Haymondia is the position of stamens throughout flowering. At the onset of anthesis, the staminal column is positioned within the keel petals ( Figure 5A ), but later moves upward until the stamens and stigma are touching the vexillum or nearly so and are fully reflexed from the wing and keel petals ( Figure 5C ). This feature is shared with several other genera to which Haymondia is loosely affiliated in phylogenies, including Apios , Mucuna , Cochlianthus , and several members of tribe Desmodieae (Egan et al., in prep.).

Figures

FIGURE 5. Haymondia wallichii. A. Habit. B. Upper leaf surface. C. Stipule scar budding, axillary inflorescence. D. Calyx, inner view. E. Flower, lateral view. F. Flower, face view. G. Vexillum. H. Wing petal. I. Keel. J. Androecium. K. Fused stamens. L. Gynoecium. M. Fruits. N. Seed. Voucher used for illustrations: A–C, E–L: A.N. Egan et al. 13-0750; D: J.D.A. Stainton 8462 (E); M–N: A. Henry 11568 (K). Illustrations by Alice R. Tangerini.

FIGURE 6. Haymondia wallichii. A. Terminal, branching inflorescence with newly-opened flowers. B. Fruits. C. Mature flowers. D. Habit and leaves. Photographs by Bo Pan.