New Species and Records of Orchidaceae from West Africa

Abstract

A medium-sized terrestrial herb, up to 60 cm tall, with succulent brown roots. Leaves up to 9 clustered towards the base of the plant, ovate to obovate, acute to acuminate, 8 - 20 x 2.5 - 5 cm; petiole up to 6 cm long. Inflorescence erect, 20 - 50 cm long, laxly 10- to 30-flowered; peduncle glabrous, grooved, bearing 3 to 4 sterile bracts on lower half; bracts lanceolate, acuminate, 11 - 21 mm long. Flowers green, not much overtopping the bracts; pedicel and ovary 13- 15 mm long. Dorsal sepal cucullate, suberect, ovate, obtuse, 6 - 7.5 x 3.5 - 4 mm; lateral sepals deflexedrecurved, obliquely lanceolate, obtuse, 8 - 8.5 x 3.5 - 4 mm. Petals bifid just above base; posterior lobe adnate to the dorsal sepal forming a hood over the column, 6.5 - 7.5 x 1.5 mm; anterior lobe short, pointing downwards, 1 mm long. Lip rather fleshy, 3-lobed at base; side lobes upcurved , linear-falcate, rounded at apex, 6 x 0.7 mm; midlobe pendent, linear, rounded at apex, 7 x 0.8 mm; spur more or less parallel to the ovary, slightly decurved or S-shaped, 13- 15 mm long. Column 33.5 mm tall; stigmatic arms shortly clavate, 1.5 mm long. Fig. 1. Habenaria thomana is newly recorded from Cameroon, and for the Flora of West Tropical Africa region, having previously been considered endemic to the island of Siio Tome. The Cameroon specimens agree well with the type collection, differing only in the attitude of the spur which is usually slightly sigmoid, rather than slightly incurved, in the material examined. I append a description of H. thomana which should appear alongside that of its closest ally, Habenaria macrandra Lindl., in the Flora of West Tropical Africa orchid account (Summerhayes 1968).