Disperis erucifera 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 : 73-75

14. Disperis erucifera H. Perrier

Not. Syst. (Paris) 5: 226 (1936); H. Perrier in Humbert H. (ed.) , Fl. Madag., 49 e fam., Orchidées 1: 191 (1939); Du Puy et al., Orch. Madag.: 134 (1999). — Type: Perrier de la Bâthie 17509, Madagascar, Montagne des Français, Diego-Suarez , Antsiranana (holo-, P!, photo K!) .

Slender terrestrial herb 10-28 cm high, with a violet stem. Leaves sessile, 2-4, alternate, 5.8- 6.2 × 1.8-3.6 cm, ovate to lanceolate, acute or apiculate, the base rounded and not clasping the stem, green above with 3 violet veins, violet below. Inflorescence 1-6-flowered; bracts leafy, to 19 × 4 mm, lanceolate, acute. Flowers violet or deep mauve-pink, relatively large; pedicel and ovary 12-15 mm long. Dorsal sepal 11 × 1-1.5 mm, linear, arched; lateral sepals 7-10 × 3-4 mm, more or less semicircular, acute, free almost to base, each with a sac-like spur. Petals 11-12 mm long, semi-ovate, with an oblong auricule on the outer side near the base, joined to the dorsal sepal to form a hood. Free part of the apical lip c. 7 mm long, covering the column, more or less notched at the base, narowed above, then dilated into a round or subrhombic lobe, densely tomentose on the upper surface. Rostellum 3 × 4 mm, with linear arms 3 mm long. — Fig. 9.

DISTRIBUTION. — Madagascar; endemic. HABITAT. — Calcareous rocks and limestone crevices in shade, in leaf debris and humus; 30- 350 m.

MATERIAL STUDIED. — W MADAGASCAR (North Sector): Bardot-Vaucoulon 427, Lac Vert area, Ankarana Massif , Diego-Suarez Prov. , 3 Mar. 1991 ( P!) ; Capuron s.n., without exact loc. ( P!) ; Cours 5467, Misoromahalana forest, Marovato-Anketraka village , Anivorano North , Diego-Suarez Distr. , 200 m, 2 Jan. 1960 ( P!) ; Du Puy & Andriantiana M715 , Antsiranana Prov., SE of Antsiranana (Diego-Suarez), NW margin of Montagne des Français, near road to Ramena and Orangea , 210 m, 12 Mar. 1994 ( K! P!) ; Humbert & Cours 32688, Diego-Suarez Prov., calcareous hills and plateaux of N Ankarana, N of Ambohipiraha road, 30- 350 m, 24 Jan.-29 Feb. 1960 ( K!, MO, P!, TAN, WAG) ; Humbert & Cours 32689, id. ( P!) ; Lewis et al. 1115, Diego-Suarez Prov., Ankarana , close to Camp des Anglais , 180 m, 18 Feb. 1994 ( MO, P!) ; Morat 3080, Ankarana, Diego-Suarez , fl. at Tsimbazaza , Antananarivo, Feb. 1970 ( P!) ; Morat 3110, cliffs of Ankarana , on calcareous rubble, Jan. 1969 ( P!) ; Perrier de la Bâthie 17509, Montagne des Français, Diego- Suarez , Jan. 1926 ( P!) ; Poisson 96, Montagne des Français, rec. 19 Nov. 1932 ( P!) ; Rakotomalaza et al. 130, Reserve of Ankarana, track to Lac Vert , 180 m, 18 Feb. 1994 ( K!, MO, P!) .

A common species of calcareous substrates in the north and north-east of the island. The leaves are purple on their underside and their upper face has three white or rosecoloured nerves. The plants, therefore, can be confused with D. trilineata when not in flower.

Figures

Fig. 9. — Disperis erucifera: A, flowering plant; B, flower, side view; C, flower, front view; D, hood; E, lateral sepal; F, column and lip, front view; G, column and lip, side view; H, pollinarium. (Morat 3080, P).