Toxicopueraria, 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 : 214-215

Toxicopueraria A.N.Egan & B. Pan, gen. nov.

Type species: — Toxicopueraria peduncularis (Graham ex Bentham) A.N.Egan & B. Pan ( Neustanthus peduncularis Graham ex Bentham , in Miquel, Pl. Jungh. 2: 235. 1852).

Diagnosis: —Woody lianas, roots not tuberous. Leaves pinnately trifoliolate. Leaflets entire. Stipules basifixed, lanceolate, open. Pseudoracemes long and pendulous, 3-several flowers clustered at each node. Bracts and bracteoles setaceous, quickly caducous. Pedicels slender. Calyx 4- or 5-lobed. Vexillum without callosities. Vexillary stamen adherent to the tube, but detaching with age. Fruits linear, flat, subchartaceous, valves not twisting upon dehiscence. Seeds elliptic, compressed.

Description: —Perennial twining, woody climber. Roots not tuberous. Stems to 40 cm in diameter when mature. Branches robust, up to 10 m long. Stipules basifixed, ovate to lanceolate, 4–10 mm × 1–3 mm, striate, persistent to caducous, leaving a raised scar. Leaves pinnately trifoliolate; petiole striate, pubescent or glabrous, 4–13 cm long; leaflets ovate to rhomboid, lateral leaflets obliquely so, glabrous to strigulose on both sides, 5–14(–23) cm × 2–8(– 14) cm, base rounded-cuneate, apex long-acuminate, margins entire, veins prominent below, pubescent, in 6 or 7 unequal pairs with basal pair opposite; petiolules pubescent, 3–7 mm long; stipels short, 1–3 mm long, persistent. Inflorescences axillary, solitary pseudoracemes, 1 or 2 per axil, pendulous, 10–40(–60) cm long, slightly nodose (with swollen nodes or brachyblasts), with (2–)4–7 flowers per node; bracts subtending the nodes, 1–3 mm long, quickly caducous; pedicels slender, thickening in fruit, to 14 mm long; bracteoles 2 per flower, hirsute, minute, caducous. Calyx 4- or 5-lobed, with short, adpressed hairs on outside, glabrous on inside, tube 3–5 mm long, gibbous above base, lobes shorter than the tube, acute to broadly so, upper two lobes connate or only almost entirely so, 1–3 mm, lateral lobes triangular, 1–2 mm long, lower lobe narrowly triangular, 1–1.5 mm long. Corolla purplish-blue to violet or white suffused with purple or pink at the tips; vexillum orbicular-ovate to obovate, apex emarginate, base clawed, auricles inflexed or truncate, without callosities; wing petals oblong; keel petals ventrally fused. Ovary elongate, pubescent, 5–8 mm long, ca. 7 ovules; style glabrous, 2–5 mm, with terminal 2–3 mm inclined towards the vexillum; stigma terminal, globose, pubescent at the base. Stamens diadelphous, the vexillary stamen adherent to staminal column at first, becoming free with age, 10–14 mm long, the free part ca. 2–3 mm, inclined upward; anthers basi-dorsifixed on alternately long and short filaments. Fruits leguminous pods, flattened-oblong, black, purple-brown, or tan, glabrous, chartaceous, (3–) 5–7 cm × 0.5–1 cm, not septate, (1–)4–7 seeded, cuneate at base, acuminate at apex, style persistent, sutures robust. Seeds compressed; funicle elongate-triangular in shape; arils elongate.

Etymology: — Toxicopueraria is derived from the latin toxicus (“poisoned”) due to the use of ground stems and roots as an insecticide and fish poison in Yunnan, China ( Perry & Metzger, 1980) and in deference to its former name, Pueraria .

Discussion: —As with Haymondia wallichii , several botanists have recognized the anomalous placement of T. peduncularis within Pueraria (see discussion under Haymondia ). Lackey (1977b) placed P. peduncularis in his group D, citing the absence of paraveinal mesophyll as evidence that the species did not belong to Pueraria , in addition to the minute bracteoles, a puckered calyx base and flat papery fruit. In spite of this, he did not create a new genus or offer any suggestions as to its affinity. Van der Maesen (1985) acknowledged these differences, but distinctly stated that he favored keeping P. peduncularis within Pueraria , stating “Even if biosystematic research would establish more distance from the other species, or even an anomalous position in the genus, it is not at all uncommon to admit within a genus a more or less anomalous species.” Although keeping P. peduncularis within Pueraria would mean fewer nomenclatural issues, it does not represent a natural or evolutionary grouping, and so we remove it and provide a new generic name here.