Disperis tripetaloides (Thou.) Lindl.

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 : 76-78

16. Disperis tripetaloides (Thou.) Lindl.

Gen. Sp. Orch. Pl.: 371 (1839); S . Moore in Baker , Fl. Maurit. and Seych.: 331 (1877); de Cordemoy, Fl. La Réunion: 254 (1895); Schlechter, Bull. Herb. Boiss. 6: 932 (1898); Feddes Repert. Spec. Nov. Regni Veg. Beih. 33: 113 (1925); H . Perrier , Not. Syst. (Paris) 5: 228 (1936); in Humbert H. (ed.) , Fl. Madag., 49 e fam., Orchidées 1: 193 (1939); Du Puy et al., Orch. Madag.: 136 (1999). — Dryopeia tripetaloides Thou., Orch. Iles Afr. : t. 2 (1822); A . Richard , Monog. Orch. Iles de France et Bourbon: 36 (1828); Bojer, Hort. Maurit.: 312 (1837). — Type: Thouars s.n., La Réunion, without exact loc. (holo-, P!, photo K!) .

Slender terrestrial herb 10-22 cm high; tubers 2, ovoid or oblong, up to 13 mm long. Leaves 2- 3 the lowest inserted in the lower third to half of stem, alternate, sessile, 1.5-3.5(-5) × 0.8- 1.7(-2.5) cm, ovate, subacute, cordate and partly enfolding the stem at the base, dark green with 5 pale nerves above, dark violet below. Inflorescence 1-4(-5)-flowered; bracts lanceolate, 0.6-1.8 cm long, shorter than the ovary. Flowers white or rose-coloured, the nerves on the back of the sepals green or brownish; the puberulence of the terminal appendage of the lip yellow. Dorsal sepal 8-9 mm long, linear; lateral sepals 7-10 mm long, c. 5 mm wide, free more or less to base, obliquely elliptic, with a sac-like spur in the middle. Petals more or less semicircular, 6-8 mm long round the curved edge, joined to the dorsal sepal to form an open hood 6.5-8.5 mm high, 3-5 mm broad. Lip joined to the column at the base, the free part 3- 4 mm long, the base triangular–cordate, more or less deeply, covered with short, dense papillae, extended above by a glabrous stalk bearing at its tip a fleshy appendage, 1-1.5 mm long, excavated on the upper surface and bearing the same short papillose puberulence. Rostellar arms curved, 2-3 mm long, rounded-spathulate at the apex. — Fig. 10.

DISTRIBUTION. — Madagascar, Seychelles, Mauritius, La Réunion and Rodrigues.

HABITAT. — Grows singly or in small colonies in rich soil and medium shade in the understorey of semi-dry forests or rarely in humid forest; sea level- 700 m.

MATERIAL STUDIED. — MADAGASCAR: Decary 4052, Fort-Dauphin , 20 June 1926 ( P!) ; Humbert 20594, Manampanihy valley ( SE) , near Ampasimena, 20-100 m, 18-23 Mar. 1947 ( P!) ; Humbert & Capuron 29042, Mt. Ankazovandamena , baie des Galions, Ranofotsy, SW of Fort-Dauphin, 21 Feb. 1955 ( P!) ; Leandri 888, Tsiandro, 10-12 Nov. 1933 ( P!) ; Leandri 1101, gorges of the Salapango, Bemaraha tsingy, calcareous rocks, 1933 ( P!); Leandri 2359, near Tsiandro ( W), Jan. 1953 ( P!) ; Perrier de la Bâthie 490, Firingalava woods, Feb. 1898 ( P!) ; Perrier de la Bâthie 15706, Sambirano, c. 400 m, Jan. 1923 ( P!) ; Scott Elliot 2305, Fort-Dauphin , May 1889 ( K!, P!) . — LA RÉUNION: Bosser 12163, St. Philippe , 200-300 m, May 1957 ( P!) ; Bosser 22166, path from Aurère to the Riv. des Galets, Cirque de Mafata , 16 June 1976 ( P!) ; Cadet 4185, Ilet Solitude, heights of La Possession, 600 m, 15 Mar. 1973 ( P!, REU) ; Friedmann 2146, Marquet ravine, Dos d’Âne, 700 m, Mar. 1973 ( P!) ; Thouars s.n., without exact loc. ( P!); Thouars in Herb. Richard s.n., without exact loc. ( P!) . — MAURITIUS: Ayres s.n., without exact loc., rec. 27 Feb. 1864 ( K!, P!) ; Commerson s.n., without exact loc. ( P!); Herb. Desvaux, without exact loc. ( P!); Vaughan s.n., Cabinet-Magenta road, 4 Apr. 1952 ( K!, MAU) ; Vaughan in MAU 11204 A, Vacoas Ridges 9 Apr. 1964 ( MAU) . — RODRIGUES: Bosser 22396, Mt. Cimetière , 16 Mar. 1978 ( P!) . — COMORES: Kirk s.n., Johanna, Aug. 1862 ( K!) ; Kirk s.n., Johanna, Nov. 1866 ( K!) ; Lavanchie s.n., Anjouan, rec. 13 Oct. 1905 ( P!) ; Pascal 414, Tschaourembo, Mayotte, 10 Mar. 1996 ( P!) ; Tinguy 746, edges of Mt. M’Lima , Combani, Mayotte, 26 Jan. 1989 ( P!) . — SEYCHELLES: Archer s.n., Praslin, Central, 800 ft., 6 Sep. 1960 ( K!) ; Friedmann 3834, Silhouette, May 1981 ( P!) ; Friedmann 3872, Glacis Noir, Praslin, June 1981 ( P!) ; Friedmann 5592, Silhouette, Jardin Marron , June 1987 ( P!) ; Guého in MAU 15382, Fond Azor, Praslin, 27 Oct. 1972 ( MAU, P!) ; Jeffrey s.n., Silhouette, ridge above Anse Lascars, 1 Feb. 1962 ( K!) ; Neville s.n., Praslin, Feb. 1867 ( K!) ; Pervillé s.n., Mahé, 21 Feb. 1840 ( P!) ; Proctor 4010, Silhouette, between La Passe and Jardin Marron , June 1960 ( K!) ; Stanley Gardiner s.n., Mare aux Cochons, 1908 ( K!); Stanley Gardiner s.n., Silhouette, 1908 ( K!); Thomasset s.n., Cascade Estate, on mossy rocks near mountain stream, May 1902 ( K!) .

Notwithstanding its extensive range, only slight variation has been observed between populations of this species, in particular in the morphology of the lip.

It approaches D. cordata in its habit and leaves which are violet on their underside. It can be distinguished readily by its free lateral sepals and the morphology of the terminal free part of the lip.

In the type collection of THOUARS ( P), the characters of the flower are not clear, but the THOUARS’ specimen in the RICHARD herbarium is in much better condition and the morphology of the lip can be clearly seen .

Figures

Fig. 10. — Disperis tripetaloides: A, flowering plant; B, flower; C, hood, front 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, lip; K, pollinarium. (Jeffrey 812, spirit material 23726, K).