Disperis johnstonii

Summerhayes, V. B., 1968, Orchidaceae (Part 1) part., Flora of Tropical East Africa 1 (1) : 219-221

2. D. johnstonii Rolfe

in F.T.A. 7: 291 (1898); Summerh. in Hook., Ic. PI. 33. t. 3269 (1935) & in F.W.T.A., ed. 2, 3: 203 (1968). Type: Tanganyika, Kilimanjaro, H. H. Johnston (K, holo.!)

Glabrous herb, 4-5-15 cm. tall, arising from a hairy globose or narrowly cylindrical tuber 0-4-1 cm. long and wide. Leaves 2, remotely alternate, sessile, sheathing at the base, rounded-ovate to ovate-lanceolate or elliptic, 0-8-3 cm. long, 0-45-2-2 cm. wide, acute or apiculate, subcordate to cordate and stem-clasping above the sheath, mostly crimson or purplish beneath. Racemes (l-)2-5-flowered; flowers white and pale purple or pink; bracts leaf-like, broadly elliptic, 0-6-1 cm. long, 3-5-7 mm. wide, acute or shortly acuminate. Intermediate sepal linear, 0-8-1 cm. long, 0-6 mm. wide, joined to the petals to form an open concave hood 0-8-1-2 cm. long, 0-7-1 cm. wide, sometimes with a purple-margined yellow spot on either side; lateral sepals obliquely semicircular, 0-8-1-4 cm., 4-5-6-5 mm. wide, obtusely acuminate, joined for about a third of their length, bearing small sacs 0-5-1 mm.

long. Petals narrowly elliptic, falcate , 0-9-1 cm. long, 2-3 mm. wide, mostly whitish with yellow apex. Lip cream or yellowish, 4-6-5 mm. long, with claw sharply bent back on itself near base and there bearing a 2-lobed appendage, the lobes diverging and papillate; claw terminating in a rounded ovate limb which bears a median densely papillate crest or protuberance. Fig. 39/2.

Tanganyika. Kilimanjaro, Old Moshi, May 1926, Haarer 178!; Ulanga District: Mahenge area, Tabora, Jan. 1932, Schlieben 1665!; Songea District: about 1-5 km. W. of Kitai near R. Nakawali, Mar. 1956, Milne-Redhead Taylor 9067!

Distr. T2, 6-8; N. Nigeria, Cameroun and Congo Republics, Malawi and Rhodesia (see note)

Hab. Brachystegia , Uapaca woodland; "grassy places under trees in mouldy clay humus soil"; " tall grass in savanna "; "with mosses in eroded gully on red soil", also (fide Schlieben) in marshy places; 500-1800 m.

Syn. D. stolzii Schltr . in E.J. 53: 548 (1915) & in F.R. Beih. 68, t. 45/177 (1932).

Type: Tanganyika, Rungwe District, Bomalakitana, Stolz 672 (B, holo f, K, iso.!) (see note)

Note. One of the two sheets of Stolz 672 at Kew is labelled " Mulinda, Mwasukulu ", the other is not precisely annotated. The maximum leaf-sizes are those given by Schlechter; I have seen nothing with leaves quite so large. A single gathering from Rhodesia seems to differ only in having the hood yellow.