Tridactyle aurantiopunctata P.J.Cribb & Stévart, Kew Bull. 59: 201 (2004).
Description:
Epiphytic herb; stem up to 19 cm, 4 - 6 mm in diameter, pendulous or spreading, covered with old leaf base; roots smooth, 1.5 - 1.9 mm in diameter. Leaves 4 - 14, subimbricate, linear, twisted at base to lie in one plane, keeled on the lower face, thin textured, 6 - 17.3 x 0.7 - 1.05 cm, unequally roundly bilobed, sometime slightly erose, lobes 1 – 9 mm long, articulate at the base to a sheathing leaf. Inflorescences up to 9, suberect, arising on the stem, below the old leaf base, 4 - 9.5 cm long, 17 - 19- flowered; rachis almost quadrangular in section, with one face papillose and concave, the others faces glabrous and convex. Flowers distichous, white with an orange spot on the column; pedicel and ovary 3 mm long, twisted at the base, papillose; bracts triangular, amplexicaul around the twisted base of the pedicel, 1.2 mm long. Dorsal sepal triangular, acute, 2.2 x 1 mm, uninerved, slightly papillose at the base of the outer face. Lateral sepals obliquely ovate-triangular, acute, slightly united at the base, 2.5 - 3.2 x 1.2 mm, uninerved, keeled, slightly papillose on the outer face. Petals linear, apiculate, 2.5 x 0.2 mm, uninerved. Lip oblong to broadly oblong, trilobed in the apical part, 2.5 - 2.8 x 1.5 - 2 mm, obscurely auriculate at the base; side lobes very short, 0.2 mm wide, erose to absent; midlobe triangular, 0.2 - 0.7 mm long, narrowly triangular; spur straight or slightly curved, compressed, apex acute, 8.5 - 9.5 x 1 - 0.3 mm. Column very short.
Etymology:
Tridactyle aurantiopunctala is named after the orange spot in the centre of the white flower.
Habitat:
Primary or old secondary forest; between 100 and 680 m. Epiphyte on 5 to 30 m tall trees. It is found growing in small clumps on medium-size branches and prefers shady places in the canopy or at 2 - 3 m above the ground.
Cultivation:
As given for the genus.
Notes:
Tridactyle aurantiopunctata clearly related to the West African Tridactyle fusifera, from which it can be distinguished by the characteristics given in the diagnosis. It is not dissimilar to the East African Tridactyle virginea P. J. Cribb & la Croix, but that has a very short inflorescence. Otherwise, this species belongs in the group of Tridactyle with long inflorescences (over 4 cm) and a trilobed lip with entire side lobes (Summerhayes 1948). It differs from Tridactyle tridactylites (Lindl.) Schltr. By its whitish flowers with an orange central spot and its shorter lip with reduced side lobes. It differs from Tridactyle armeniaca (Lindl.) Schltr. by its reduced lip side lobes and its smaller habit.
Distribution:
Príncipe
References:
World Checklist of Monocotyledons. The Board of Trustees of the Royal Botanic Gardens, Kew. Published on the Internet; http://www.kew.org/wcsp/monocots/ accessed 21.03.2017
Images:
Click on each image to see a larger version.
