Disperis anthoceros var. humbertii (H. Perrier) la Croix, 2002

Croix, Isobyl la, Bosser, Jean & Cribb, Phillip J., 2002, The genus Disperis (Orchidaceae) in Madagascar, the Comores, the Mascarenes and the Seychelles, Adansonia (3) 24 (1), pp. 55-87 : 58

— Disperis anthoceros var. humbertii (H. Perrier) la Croix , comb. et stat. nov.

Disperis humbertii H. Perrier, Not. Syst. (Paris) 8: 35 (1939); in Humbert H. (ed.), Fl. Madag., 49 e fam., Orchidées 1: 180 (1939); Du Puy et al., Orch. Madag.: 134 (1999). — Type: Humbert 14212, Madagascar, forest of Analavelona (holo-, P!, photo K!) .

Slender terrestrial herb 8-15 cm tall. Tubers 2, c. 8 × 5 mm, ovoid. Leaves two, opposite, sessile, set about the middle of the stem, 13-22 × 11-16 mm, ovate, acute. Inflorescence 1-2-flowered; bracts leafy, c. 7 × 4 mm. Flowers white; pedicel and ovary 7-9 mm long. Dorsal sepal joined to petals to form a slender, erect spur 7-9 mm long from apex of spur to top of ovary; lateral sepals 7 × 3.5 mm, obliquely ovate, joined at the base for from quarter to half of their length, each with a sac-like spur c. 1 mm long, around the middle. Petals c. 7 × 4.5 mm, falcate, adnate to the dorsal sepal. Lip joined to column at base, then with a linear claw which almost reaches the tip of the spur, then is bent back for c. 1 mm, bearing at its apex an appendage of 2 fimbriate lobules 1-1.5 mm long.

DISTRIBUTION. — Madagascar; endemic. This variety of the African species is known only from a single collection. The typical variety is widespread in tropical Africa.

HABITAT. — In ravine with bamboos, on basalt and sandstone.

MATERIAL STUDIED. — MADAGASCAR: Humbert 14212, forest of Analavelona, N of Fiherenana, 950- 1250 m, Mar. 1934 ( P) .

The flowers of Disperis humbertii differ from those of D. anthoceros only in being slightly small- er. In the typical form of D. anthoceros , the spur is 12-20 mm long, while in var. grandiflora Verdc. from Tanzania, the spur is 23-30 mm long.