MUCUNA ADANS. (LEGUMINOSAE) IN THAILAND (C.M. WILMOT-DEAR)
Notes.— M. thailandica appears to be very rare and local, known only from ten collections from Doi Inthanon (all material seen is cited here). It is distinguishable from all other Thai taxa in its very large calyx and corolla (especially the standard petal which is at least 5 cm long rather than at most 3.5 cm) and from all except M. macrocarpa in its long linear fruit and absence of persistent stipels; M. macrocarpa is easily distinguished from it in flower (corolla shorter with some parts purple and with a pubescent apical border, wing relatively broad), but is very similar in fruit, differing only in its fruits usually being shorter, mature leaflets which are often hairy, with the terminal leaflet slightly relatively narrower, and lateral leaflets more asymmetrical.
3. Mucuna gigantea (Willd.) DC., Prodr. 2. 405. 1825; Ridley, Fl. Lower Siam in J.Straits Branch Roy. Asiat. Soc. 5 1:93. 1911; Gagnep. in H.Lecomte, Fl Indo-Chine 2: 318. 1916; Ridley, Fl. Malay Penins. 1:577. 1922; Craib, Fl .Siam 1: 443. 1928; Merrill in Trans. Amer. Philos. Soc. 24: 210. 1935;Van Thuan, Fl. Camb. LaosVietnam 17: 35 & 37, Fig. 3. 1979. Type: Rheede, Hort. Malab. 8: 63 t.36 (1688). Figs. 1A–C, 2A–C.
subsp. gigantea; Wilmot-Dear, Kew Bull. 45: 5 & Fig 1. 1990 & Kew Bull. 47: 213.
Large sprawling climber; stems, petioles and leaflets glabrous or sparsely fine- adpressed-hairy. Leaves with terminal leaflet 7–13 by 4–8.5 cm; elliptic-ovate (sometimes elliptic or rhombic), length/width ratio ca 2:1, apex short-acuminate, base rounded, lateral veins 4–6, gently curved; lateral leaflets markedly asymmetrical with width ratio of abaxial to adaxial halves ca 2.2:1, base of abaxial half rounded to slightly cordate; rather thin- chartaceous; stipels 3–5 mm long. Inflorescences axillary, 8–25 cm long, often branched near apex, ultimate branchlets few–6, all crowded at apex, these and pedicels of very varying lengths, progressively shorter near apex such that inflorescence is distinctly corymbose or “pseudumbellate” even in young bud stage; pedicels and axis with short, fine, pale pubescence; bracts narrowly ovate to elliptic, 3–5 mm long, caducous, bracteoles 6–18 by 5–7 mm, distinctly longer than calyx and persistent to well-developed bud stage. Calyx pubescent like pedicels and with abundant irritant bristles, tube 8–10 by 11–15 mm, lobes short and broad, lowest (1–) 2–3 mm long, laterals 1–2 mm. Corolla white, tinged green, yellow or pink; standard 2.5–3 (–3.8) cm long, large relative to keel –[ times keel length; wings 2.8–4 by 0 8–1 cm, equalling keel length. Fruit leathery, asymmetrically oblong or elliptic-oblong, (1–) 3 (–4)-seeded, (7–)10–15(–18) by (3.5–)4–5.5(–6) cm, length up to 3 times width, markedly laterally flattened, up to 0.5 cm thick, surface with sparse fine, brown pubescence and scattered bristles but glabrous with age, also ornamented with a pattern of strongly raised vein-lines so close and fine as to give a pitted appearance; each margin with a pair of conspicuous wings 5–10 mm broad. Seeds dark brown or black, 2–3 by 1.8–2.5 cm.
Thailand.—NORTHERN: Chiang Mai [Kerr 33 (BM)]; CENTRAL: Bangkok; SOUTHEASTERN: Trat [Ko Kadat, Schmidt 568 & 577a. (C)]; PENINSULAR: Ranong [Fukuoka et al.s.n. (BKF)], Nakhon Si Thammarat, Satun, Songkhla [Maxwell 85–631 & 85–741,
(BKF, GH, L)].
Distribution.— Widespread throughout Asia and Pacific, especially coasts and Islands; Japan, India, Burma, Indochina, Indonesia, Philippines, Australia, Pacific islands.