HAIGH A., WILKIN P., RAKOTONASOLO F. 2005. A new species of Dioscorea L. (Dioscoreaceae) from western Madagascar and its distribution and conservation status. Kew Bulletin, 60(2): 273-281.

Abstract :

A new species of compound-leafed yam, Dioscorea bosseri Haigh & Wilkin is described and illustrated. It differs from D. bemarivensis Jum. & H. Perrier through having trifoliolate leaves on all stems. D. bemarivensis is always pentafoliolate, at least at the stem base.

In addition, male flowers of D. bosseri are usually solitary and the anterior leaflet has three main veins, while in D. bemarivensis there are usually at least some flowers arranged in cymules on male inflorescences and the anterior leaflet usually has a single main vein.

Petiole and petiolule lengths and tepal dimensions also differ between the two species, and while their ranges overlap, t-tests show that their means are significantly different.

A distribution map and conservation assessment are provided; the former suggests that these two closely related species may have been a product of sympatric speciation.

In common with several other apparently unrelated species of Dioscorea from Madagascar (and D. bemarivensis), D. bosseri has unusual flattened, deltoid, translucent hairs on its leaves.

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