AFRICAN

ORCHIDS

Aeranthes tricalcarata H.Perrier, Notul. Syst. (Paris) 8: 43 (1939).
Description:
Plants 20-40 cm tall; roots white and thick: stem elongated (20-40 cm.), branched, compressed, 3- 4 mm. wide with the sheaths. Leaves numerous distichous, very thin; sheaths 5-10 mm, compressed, traversely rugose carenate marginally and heavily 10 veined on each face; limbus widely linear (2-6 x 0.6- 1 cm.) amplexicaul basally and slightly attenuate toward the unequally bilobed-obtuse apex. Inflorescences single flowered bearing a single sheath, much shorter than the leaves; peduncle very short, 5 mm long at most, concealed by the sheath, bracts scarious-brown, tubular, obtuse, 3-3.5 mm long; pedicel 10 - 13 mm long, 3 winged: flowers entirely green when live, brownish-black when dry. Sepals oval-lanceolate-acute (26-27 x 7 mm,), with 7 fine well branched veins, the laterals slightly wider basally, enlarged on the front margin and joined to the column foot. Petals oval-lanceolate (24-26 x 7-8 mm.), attenuate from the center to the acute apex and with 7 fine well branched veins. Labellum inserted in front of the column foot with a wide unguis (4.5 mm.), enlarged above in a suborbicularor widely oval (13 x 9 mm. and more) lamina, notched in front. 6 veined in the unguis, which branch many times in the enlarged portion and anastomosing in wide areas near the margins. Column curved apically, 7 mm. long; foot well developed very concavely boat like, 12 mm. long, with the lateral margins nearly as tall (10 mm.), the front margins enlarged in rounded lobes above the unguis of the labellum, in the deep pits of the 3 spurs, and in front of the orifaces of these 3 spurs with a bifid keel, thick and slightly projecting; lateral spurs triangular-obtuse, wider basally (8 mm) than tall (5 mm.), straight and pendent; median spur to the contrary with a narrowed oriface, curved apically, and 10 mm long, clavate-obtuse, gradually attenuate toward the base; margins of the clinandrium very thick behind; auricles thin. well developed, in the shape of an axe head-angular with the 2 margins, 1.5 mm tall, wider apically (1,2 mm.) toward the base, very different in tint and hue of coloration from the front margins, thick and dark. from the clinandrium; median tooth of the rostellum forming a thick, rigid horn, curved in front and 0,8 mm long. Anther subcarintae (3 mm. long and wide). elongated ru front by 2 obtuse lobes, separated by a narrow trench; thin thread-like, l mm, inserted at the back edge of the very thick clinandrium: pollina 2, elliptical-narrow (1.2 x 0.4 mm.); cauda retracted; retinacle common, of the same form and length as the pollina, but narrower.
Habitat:
Lithophyte: from rocky, shady crags, from 1200 m. alt, flowering December.
Cultivation:
As given for the genus.
Distribution:
SW. Madagascar.Endemic.
References:
WCSP (2017). 'World Checklist of Selected Plant Families. 21.01-2017; http://apps.kew.org/wcsp/
Images:
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