Sohmaea laxiflora (DC. 1825a: 100) H.Ohashi & K.Ohashi (2018b: 162)

Saisorn, Witsanu & Chantaranothai, Pranom, 2022, A taxonomic revision of two genera, Pleurolobus and Sohmaea (Leguminosae) in Thailand and Indo-China, Phytotaxa 573 (2), pp. 231-246 : 239

3. Sohmaea laxiflora (DC. 1825a: 100) H.Ohashi & K.Ohashi (2018b: 162) .

≡ Desmodium laxiflorum DC.

Type:— NEPAL. Wallich s.n. (lectotype G-DC! G00479839 , designated here, isolectotypes G!, G-DC! G00479877, G-DC! G00479873) .

≡ Meibomia laxiflora (DC.) Kuntze (1891: 196) .

= Desmodium macrophyllum [ Desv. 1813: 122, nom. nud.] Desv. (1826: 306). Type :— India orientalis, S.N. (lectotype P! P02937969 (pro parte) [digital image], designated here, isolectotype P! P02937970 (pro parte) [digital image]) .

= Hedysarum recurvatum [ Roxb. 1814: 57 , nom. nud.] Roxburgh (1832: 358). Type :— INDIA. Kanpur (Cawnpore), introduced by Captain Hardwicke in 1802, Roxburgh s.n. (syntype BR! BR0000009894372 [digital image]).

≡ Desmodium recurvatum (Roxb.) Wallich (1831: 197) .

Small shrub, 0.2–1.5 m high; stems and twigs terete to angular, glabrous to appressed pubescent and uncinate. Leaves trifoliolate, rarely unifoliolate on lower part, spirally arranged; stipules triangular to narrowly triangular, 7–8 × 2– 3.5 mm, apex long acuminate, surface glabrescent to pubescent; petioles 1–4.5 cm long, glabrescent to pubescent and uncinate hairy; rachis 0.8–2.5 mm, glabrescent to pubescent and uncinate hairy. Leaflets: stipels triangular to narrowly triangular, 1–10 × 0.3–1 mm, apex acuminate to long acuminate, surface glabrescent to pubescent; petiolules 1–5 mm, glabrescent to densely pubescent. Terminal leaflet broadly elliptic, orbicular, cordate, lanceolate to broadly obovate, 3–19 × 3–18 cm, apex rounded, acute to acuminate, base cordate, subcordate to truncate, attenuate, cuneate, obtuse to rounded, margin entire, upper surface glabrous or uncinate and sparsely appressed pubescent, lower surface soft pubescent, without uncinate hairs; lateral veins 6–13 per side, conspicuous. Lateral leaflets obliquely ovate or lanceolate, 3–12.5 × 1.5–6 cm, apex acute to acuminate, base obtuse to rounded, margin entire, both surfaces like terminal leaflet; lateral veins 7–9 per side, conspicuous. Inflorescences simple or rarely paniculate, 5–50 cm long, terminal or axillary; rachis sparsely to densely pubescent and uncinate hairy. Primary bract narrowly triangular to ovate, 1.8–5 × 0.3–1 mm, apex pointed, margin fimbriate, surface glabrescent to pubescent, distinctly veined, enclosing 3–6-immature flowers and secondary bract. Secondary bract narrowly triangular to linear, curved or straight, 1.8–3 × 0.3–0.5 mm, glabrescent to pubescent. Flowers 4–4.5 mm long, 3–6-flowered fascicles; bracteoles absent; pedicels 2.5–4.5 mm long, long sparsely pubescent and densely uncinate. Calyx greenish white, 1.5–3 mm long, base cuneate to obtuse; outside long pubescent and uncinate, inside glabrous, tube 1–1.3 mm long; teeth 0.8–1.5 mm long, ±equal to tube length, lower most prominently longer than others, upper one entire at the apex, not divided. Corolla : standard white, wings and keels violet; standard broadly obovate to obovate, 4–5 × 3–3.5 mm, apex emarginate, base attenuate, not auriculate, claw 0.5–1 mm long; wings narrowly oblong, 3.5–5.5 × 1–1.3 mm, apex obtuse, base auriculate, 0.3–0.5 mm long, claw 0.5–1.5 mm long; keels narrowly oblong, curved, ca. 4 × 1 mm, apex acute, base not auriculate, claw 1–1.5 mm long. Stamens 4–5 mm long; anthers ellipsoid, 0.3–0.5 × 0.2–0.3 mm. Gynoecium 3.5–6.5 mm long; ovary oblong, laterally compressed, minutely uncinate, shortly stipitate, 7–10-ovulate; style 1.5–2 mm long, glabrescent; stigma minutely capitate. Pods brown, sessile or shortly stipitate, indehiscent, 5–11-articulate, subterete, 2–4.5 cm long, 1.3–1.8 mm wide, surface densely uncinate, smooth, both upper and lower sutures straight or less constricted; isthmus 2/3–5/6 as broad as the pod; articles linear-oblong, 3–4.5 mm long; fruiting pedicels 4–6 mm long, pubescent and densely uncinate. Seeds dark brown, transversely oblong, 2.2–3 × 0.8–1 mm, 0.5–0.7 mm thick.

Key to subspecies

1. Leaves unifoliolate. Upper tooth of calyx shallowly divided......................................................................................3.1 subsp. lacei

1. Leaves trifoliolate, rarely unifoliolate. Upper tooth of calyx entire..................................................................... 3.2 subsp. laxiflora