Disperis hildebrandtii Rchb.

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

8. Disperis hildebrandtii Rchb. f.

Otia Bot. Hamb: 73 (1881); Bot. Zeitung (Berlin) 39: 449 (1881); Schlechter, Bull. Herb. Boiss. 6: 929 (1898); Feddes Repert. Spec. Nov. Regni Veg. Beih. 33: 108 (1925); H. Perrier in Humbert H. (ed.) , Fl. Madag., 49 e fam., Orchidées 1: 184, (1939); Du Puy et al., Orch. Madag.: 134 (1999). — Type: Hildebrandt 3158, Madagascar, Lokobé, Nosy-Bé (holo-, W; iso-, BM, K!, P!) .

Slender terrestrial herb 7-25 cm tall. Tubers c. 10-20 × 5-10 mm, ovoid. Leaves 1-3, alternate, in upper half of stem, 1.5-7 × 0.5-2 cm, lanceolate, acute, clasping the stem at the base. Inflorescence 1-3(-6)-flowered; bracts leafy, 14- 40 × 3-10 mm. Flowers erect or suberect, pale rose in colour; pedicel and ovary 4-9 mm long. Dorsal sepal 8-10 × 1 mm, linear; lateral sepals 8- 10 × 3-6 mm, joined in the basal half, semiovate, each with a deep spur near the middle. Petals 8-11 × 3-5 mm, adnate to the dorsal sepal and forming a broad, concave hood about 10 mm tall and 12 mm wide; the apex of the petals slightly overtops the dorsal sepal. Lip joined to the column at base, narrowly cylindrical above that and then enlarged, bearing at the top a 3-lobed appendage, the 2 lateral lobes short, 1.5- 2 mm long, thick, erect but slightly curved, densely covered with a short pubescence of papillose hairs, the mid-lobe 5 mm long, pendent, arched, tongue-shaped, without a stalk to the side lobes, with a short pubescence of small paipillose hairs on the sides and beneath, and carrying on the upper surface longer dense calvate-vesicular hairs. Rostellum 2.2 × 1.5 mm, with arms 1.7 mm long, spathulate at the tip. — Figs. 6C , 7A.

DISTRIBUTION. — Madagascar; Comores.

HABITAT. — Quite frequent in the understorey of humid to semi-dry woodland and forest in the N-NE and Centre of Madagascar and on Mayotte, on laterite soils derived from gneiss or from basalt; 90-1400 m.

MATERIAL STUDIED. — MADAGASCAR: Cremers 1438, road to Lakato, near Périnet, 16 Feb. 1971 ( P!) ; Decary 15290, Ankazomanga, Vakinankaratra , 6 Dec. 1939 ( K!, P!) ; Hildebrandt 3158, Nosy-Bé, Lokobé Mt. , Sep. 1879 ( K!, P!, W!) ; Humbert 23199, valley of Androranga , tributary of Bemarivo ( NE) , between Doany and Anketsahely, 400-700 m, 10-12 Feb. 1949 ( P!) ; Humbert 28201, ibid., Ravine Beamalonakely , 300-400 m, 10 Dec. 1949 ( P!) ; Humbert & Capuron 24226bis, valley of Andalangy , tributary of the Androranga, basin of the Bemarivo of the NE, 700- 800 m, 12-14 Nov. 1950 ( P!) ; Humbert & Capuron 25337, Mts. to the N of Mangindrano ( High Maevarano ), towards the summits of the Ambohimirahavavy, valley of Ambatohafo, 1200 m, 19 Jan.-12 Feb. 1951 ( P!) ; Humbert 32144, near Diego-Suarez, Ambre forest , 1000 m, 23 Dec. 1959 – 18 Jan. 1960 ( K!, P!, TAN!) ; Perrier de la Bâthie 15193, Sambizano forests, Oct. 1922 ( P!) ; Perrier de la Bâthie 15708, Mt. Tsarantanana , 1000-1400 m, Jan. 1923 ( P!) ; Seyrig 485, Belambo forest , N of Ampandrandava, 1000 m, Jan. 1943 ( P!) . — COMORES: Labat & Pascal 2900, Mayotte, massif of Benara , N slope in climbing on the Lima Tchaourembo, 350 m, 8 Dec. 1996 ( P!) ; Labat et al. 3284, Mayotte, Chiconi , Sohoa Forest Res., 90 m, 24 Nov. 2000 ( G!, K!, Mayotte, P!) ; Tinguy 977, 1035, Mayotte, Choungi , 6 Oct. 1989 ( P!) ; Tinguy 1056, Mayotte, 2 Nov. 1989 ( P!) .

The flowers are white, lined or striped with pale rose-pink or rose-purple. LABAT provides more details of specimens from Mayotte which have white sepals touched with rose, a green spur, the rest white with two rose-violet bands, a lip with two rose lateral lobes and a white hairy terminal appendage. The vesicular hairs of the lip appendage are very characteristic.

Figures

Fig. 6. — Appendage of lip: A, Disperis majungensis (Perrier de la Bâthie 13038); B, Disperis cordata (Cadet C11, in alcohol); C, Disperis hildebrandtii (Hildebrandt 3158); D, Disperis ciliata (Humbert & Capuron 25002); E, Disperis lanceana (Lance s.n.); F, Disperis saxicola (Bosser 17168); G, Disperis humblotii (Humblot 1592); H; Disperis perrieri (Humbert & Capuron 25758); I, Disperis oppositifolia var. mascarenensis (Bosser 21622).

Fig. 7. — Flowers of Disperis species: A, D. hildebrandtii; B, D. saxicola; C, D. discifera; D, D. oppositifolia var. oppositifolia; E, D. oppositifolia var. mascarenensis; F, D. masoalensis. (A, D, F, photos J.-N. LABAT; B, C, E, photos J. BOSSER).