Disperis ankarensis H. Perrier

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 : 67-71

9. Disperis ankarensis H. Perrier

Not. Syst. (Paris) 8: 129 (1939); in Humbert H.

(ed.), Fl. Madag., 49 e fam., Orchidées 1: 186 (1939);

mm 1

E

Du Puy et al., Orch. Madag.: 133 (1999). — Type: Humbert 18825 (= Humbert 18986), Madagascar, Ankarana, N of Ambilobé , Jan. 1938 (holo-, P!, photo K!). Known only from the type collection .

Slender terrestrial herb 14-18 cm high. Tubers 2, up to 2 × 1.2 cm, ovoid, villous. Leaves 2, in the upper half of the stem, alternate, 3.5-5 × 0.5-1 cm, narrowly lanceolate or linear-lanceolate, forming a funnel-shaped sheath at the base that clasps the stem. Inflorescence 1-3-flowered; bracts leafy, 18-32 × 3-4 mm. Flowers with green sepals, veined with pink, petals pink; pedicel and ovary 8-9 mm long. Dorsal sepal 8 mm long, linear, forming with the petals a broad, very concave hood c. 8 mm high and 15 mm wide; lateral sepals 7 × 3 mm, joined near the base, falcate, the tips curling in, each with a sac-like spur in the basal half. Petals hyaline. Lip erect part joined to the column for most of its length with only a short free part; appendage 3-lobed; mid-lobe 3.5- 5 mm long, fleshy, tongue-shaped, rounded at the apex, slightly sigmoid in profile, not stalked, carrying long hairs on the upper surface and short papillae beneath; side lobes 2-3 mm long, linear-oblong, glabrous or with short papillae on the upper surface, arching and curving to the side, narrower than the mid-lobe and twisted at the tips. Rostellum lobes very broad and thick with hyaline, spathulate arms, twisted and geniculate at the base. — Fig. 8.

NOTE. — The description given in the Flore de Madagascar does not seem to match the drawing on the type sheet (which is described here) .

DISTRIBUTION. — Madagascar; endemic.

HABITAT. — Terrestrial in semi-dry forest of the W, growing in the humus amongst calcareous rocks; c. 300 m.

This species is only known from the type. The flower shows affinities with D. hildebrandtii but it is distinguished readily by the nature of the hairs of the terminal appendage of the lip.

PERRIER DE LA BÂTHIE, in his protolog, cited a single specimen (Humbert 18825). However, the only specimen at P is Humbert 18986 with the same locality and date. There is a single collection as can be seen from the fact that HUMBERT’ s field

Figures

Fig. 8. — Disperis ankarensis: A, flowering plant; B, flower; C, hood, side view; D, dorsal sepal; E, lateral sepal; F, petal; G, column and lip, front view; H, column and lip, back view; I, column and lip, side view; J, pollinarium; K, lip. (Humbert 18986, P).