MUCUNA ADANS. (LEGUMINOSAE) IN THAILAND (C.M. WILMOT-DEAR)
distinctly lengthened, 3–4 mm; pedicels (1.5–) 2 cm, these and axis with denser hairs than stem, somewhat spreading, > 0.4 mm long; bracts caducous, bracteoles fairly persistent, slightly exceeding calyx, narrowly ovate, 12 by 6 mm. Calyx densely hairy like pedicels, tube ca 8 by 14 mm, lowest lobe 7–8 mm, laterals 4–5 mm long, all narrow < 2 mm wide, long- acuminate. Corolla purple, small, standard ca 3 cm long, wings ca 4.5 by 1.2 cm, apex tapering, keel ± equalling wing. Fruit leathery, 2-seeded, narrowly oblong, somewhat constricted between seeds, 5–9 by 2.5–4 cm, markedly laterally flattened up to 1 cm thick, with dense coarse, irritant bristles and sparse shorter, finer bristles, faces with 12–15 obliquely transverse, ± parallel, simple, thin-textured narrow lamellae of irregular height, 1– 2 mm irregularly widening to 4 mm, mostly interrupted near middle of pod and all extending to distal edge of marginal wing, each margin with a pair of wings 3–4 mm wide but with irregularly dentate outline, widening to 5–6 mm where lamellae run into it. Seeds black, 2–2.4 by 1.5–1.8 cm, hilum black.
Thailand.— PENINSULAR: Krabi [Larsen 43470 (GH)], Trang [Phusomsaeng et al. 49 (AAU, K, L)], Satun [Congdon & Hamilton 296 (A); idem, Maxwell 87–361 (BKF, GH, L)], Songkhla [Maxwell 86–64 (BKF, GH, L, MO)].
Distribution.— Southern Peninsular Thailand and the northern border of Peninsular Malaysia
Ecology.— Evergreen and secondary forest, open thickets near streams or by seashore; sea level to 150 m
Notes.— M. stenoplax appears to be rare and localised; only five collections (cited above) have been seen from Thailand and one from Peninsular Malaysia. Even young fruits can be distinguished from most Thai species in having lamellae of irregular height extending to the distal edge of the marginal wing which is wider at this point, giving a jagged irregularly dentate appearance; it is frequently misidentified as M. biplicata (Peninsular Malaysia, not recorded from Thailand) which has similar leaves and superficially very similar fruits but differs in that its fruit lamellae are bifurcated (rather than simple raised flaps) and calyx lobes much shorter. M. stenoplax is ± indistinguishable vegetatively from three other lamellate-fruited Thai species, M. hainanensis, M. interrrupta and M. revoluta, but distinguished from the first two (often all three) by its distinctly lengthened, rather than knob-like, ultimate inflorescence branchlets. Its flowers are smaller than in M. interrrupta and often in M. hainanensis but of similar size to those of M. revoluta, which differs in that its calyx lobes are broadly acute and its axis and pedicels with minute (0.1–0.2 mm rather than ca 0.4 mm), spreading pubescence.
7. Mucuna hainanensis Hayata, Icon. Pl. Formos. 3:72. 1913; Van Thuan, Fl. Camb. Laos Vietnam 17: 39. 1979.Wilmot-Dear, Kew Bull. 46: 205–212. 1991. Type: China, Hainan [May 1910, Katsumada s.n. (holotype TI!; ?isotype K!)].
subsp. hainanensis; Wilmot-Dear, Kew Bull 46: 207 & Fig. 1 J–N .1991 & Kew Bull. 47: 218 & Fig. 7 C–D. 1992.— M. suberosa Gagnep. in Notul. Syst. (Paris) & in H.Lecomte, Fl Indo-Chine 2: 319. 1916. Types: Vietnam, Tonkin [D’Aleizette 345, Balansa 2260, Bon 2925 & 332 (syntypes P!), Balansa 2257 (syntype P!; isosyntypes AAU!, K!), Balansa 4402, Bon 2938 (syntypes P!; isosyntypes K!)].— M. nigricans sensu auctt. non (Lour.)