Tridactyle thomensis P.J.Cribb & Stévart, Kew Bull. 59: 199 (2004).
Epiphytic herb; stem up to 100 cm, 4 - 5 mm in diameter, pendulous, covered with old leaf base, few branched; roots 3 - 4 mm in diameter. Leaves thintextured, 4 - 14, 2.3 - 3.2 cm apart, linear, twisted at base to lie in one plane, keeled on the lower face, 7.1 - 13 x 0.6 - 1.1 cm, unequally roundly bilobed, lobes 1 - 9 mm long. Inflorescences up to 6, patent, arising opposite the leaves or on the stem below the old leaf bases, 2.2 - 3.1 cm long, 7 - 10-flowered; rachis in zig-zag, almost quadrangular in section. Flowers distichous, white; pedicel and ovary 2 - 2.5 mm long, twisted at the base, sometimes papillose; bracts triangular, amplexicaul around the twisted base of the pedicel, 1.5 - 2.5 mm long. Dorsal sepal ovate to oblong, acute, 2.2 - 2.5 x 1.5 mm. Lateral sepals obliquely ovate, apiculate, 2.2 x 1.2 mm. Petals linearspathulate, acute, 2.5 x 0.2 mm, bidentate toward the apex. Lip obovate, trilobed in the apical part, 1.7 x 1- 2.2 mm, slightly auriculate at the base; side lobes very short, triangular, erose; midlobe triangular, 0.2- 0.7 mm long, curved upwards; spur straight or sigmoid, compressed, slightly swollen at the apex, apex obtuse, 7.8 - 8.5 x 1.3 mm. Column 1 mm high.
Tridactyle thomensis is named after the island of Sáo Tomé.
Old plantations and secondary forest; 0 - 830 m. Epiphyte on branches and trunks of trees, in particular on Dracaena arborea K. Koch.
It is easy to grow under shady conditions. Flowering period; January, November, December.
Tridactyle thomensis, belonging to a group with short to medium (1- 4 cm long) inflorescences and an usually trilobed lip (Summerhayes 1948), is related to Tridactyle fusifera from which it differs in its straight or sigmoid, longer, terete spur and bidentate petals.
São Tomé
World Checklist of Monocotyledons. The Board of Trustees of the Royal Botanic Gardens, Kew. Published on the Internet; accessed 21.03.2017
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