THAI FOR. BULL. (BOT.) 36: 114–139. 2008.
Mucuna Adans. (Leguminosae) in Thailand
ABSTRACT. Keys and descriptions are provided for the fourteen species of Mucuna Adans. recorded from Thailand (thirteen native, one cultivated); two additional species from peninsular Malaysia are included in the key.
KEYWORDS: Leguminosae, Mucuna, Thailand, taxonomy, species.
This regional revision of Mucuna has been prepared for the Flora of Thailand and is an updated version of earlier work (Wilmot-Dear 1992 & 1993). Thirteen species are native to Thailand; three, M. thailandica Niyomdham & Wilmot-Dear, M. oligoplax Niyomdham & Wilmot-Dear and M. gracilipes Craib, are endemic, M. stenoplax Wilmot-Dear extends to Peninsular Malaysia and the remainder are more widespread, extending to the Indian subcontinent and/or China and Indochina. One species, M. gigantea (Willd.) DC, is widespread throughout Asia and the Pacific. Two Indonesian species which extend to Peninsular Malaysia, M. acuminata Grah. and M. biplicata Teysm & Binn ex Kurz, may also possibly occur in Thailand (the latter is recorded from the adjacent northern part of Perak) and are therefore included in the key. A further Indonesian species, M. warburgii Lauterb. & K. Schum., has been cultivated in Thailand.
A note on specialised characters useful in identification. Two pairs of stipels (small, terete, stipule-like structures) are often present on the leaves, the lower pair either side of the petiole at its junction with the petiolules of the lateral leaflets, the upper pair at the junction of the apex of the rachis and the base of the petiolule of the terminal leaflet; these stipels are consistently either persistent on very old leaves or absent from even very young leaves. Flowers are pedicellate, arising in a group of (usually) three from the apex of very short secondary axes (in this paper termed “ultimate branchlets”) which are either distributed ± uniformly throughout the main flowering axis or restricted to its distal part and are either reduced to small knobs (most species) or lengthened into distinct secondary peduncles; the main axis is mostly otherwise unbranched but sometimes several-branched near the base. The shapes and proportions of the calyx lobes and the relative lengths of the lowest and lateral lobes are consistent distinctions between certain species. Corolla colour is not always reliable because certain species may have white and purple variants. Petals are often hairy at the extreme base but indumentum elsewhere on the corolla is uncommon; presence or absence of a distinctly pubescent margin around the apex of the standard and
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