Aerangis oligantha Schltr., Bot. Jahrb. Syst. 53: 599 (1915).
Description:
Stem woody up to 4 mm diam., up to 6 cm long, closely covered by over- lapping leaf bases, with numerous slender, flexuous, greyish white roots to 2 mm diam. Leaves 4-8, alternate, spreading or erect, up to 4 mm apart, oblanceolate or narrowly spathulate, base sheathing, apex bilobed, lobes acute, 4-15 mm long, sometimes one lobe much shorter or absent, rather thin and leathery in texture, dark green, margins entire, up to 8 x 2 cm just below the apex. Inflorescences axillary, or from the woody stem below the leaves, often arising from the site of previous inflorescences, usually erect, bearing few to 12 flowers, 1-5-4 cm long; peduncle very short, terete; rhachis straight; bracts triangular, acute, 1.5-3 mm long. Flowers very close together, crowded towards the apex of the rhachis and not always Resupinate, pale green when first opening, becoming white, 15-18 mm diam., all tepals spreading; pedicel with ovary straight 10-15 mm long. Dorsal sepal lanceolate-oblong, 6-9 x c. 3 mm; lateral sepals slightly falcate 6-10 x 2 mm. Petals lanceolate-elliptic, 6-9 x 3-3-5 mm. Lip ovate, apiculate, 6-8-5 x 4 mm; spur parallel to the pedicellate ovary, slightly swollen in the lower half, 8-13 mm long. Column small, 2 mm long; androcilnium sloping, centre of anther cap with a green vertical stripe; rostellum straight and directed downwards towards the spur; pollinia globose; stipes slender; viscidium broadly elliptic, or rounded and fitting over the swollen end of the rostellum. Fruit a capsule 15-30 x 3 mm.
Habitat:
On low bushes and small trees, always amongst mosses and lichens; 1800-2100 m.
Cultivation:
As given for the genus.
Notes:
It is unusual, in the genus, in having the flowers crowded together on a very short rhachis. It is hard to see why Schlechter chose the specific epithet 'oligantha' (few-flowered) unless the specimen of Stolz 2399 which he saw was very poor. Usually this species gives the impression of an abundance of flowers owing to their crowded arrangement. Schlechter (I.c.) remarked that it should be placed close to Aerangis hyaloides (Reichb. f.) Schltr. of Madagascar. The larger and more numerous flowers, together with the plant size and leaf shape, clearly distinguish it from that species.
Distribution:
SW. Tanzania to N. Malawi
References:
La Croix, I. & Cribb, P.J. (1998). Orchidaceae (Part 2) Flora Zambesiaca 11(2) Page 390; La Croix, I. et al. (1991). Orchids of Malawi A.A. Balkema, Rotterdam Page 252; A Revision of the African Species of Aerangis (Orchidaceae) Kew Bulletin, Vol. 34, No. 2 (1979), pp. 239-319; WCSP (2017). 'World Checklist of Selected Plant Families. 19.01-2017; http://apps.kew.org/wcsp/
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