Disperis katangensis

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

1. D. katangensis Swnmerh .

in K.B. 1931: 384 (1931) & in Hook., Ic. PI. 33, t. 3271 (1935). Type: Congo Republic, Katanga, Kisinga valley, von Hirschberg 168 (K, holo.!)

Glabrous herb, 5-5-14 cm. tall, arising from a hairy ellipsoid tuber 05- 2 cm., 5-8 mm. wide. Leaves 2-3(-4), alternate or rarely the lowest pair subopposite (but at least 1-2 leaves always distant), sessile, sheathing at the base, ovate or rounded-ovate, 0-9-2 cm. long, 0-7-1-8 cm. wide, acuminate or shortly apiculate at the apex, cordate and clasping the stem above the sheath, mostly purplish beneath, the venation mostly whitish. Flowers solitary or in 2-4-flowered racemes, white to pinkish-mauve or purplish; bracts leaf-like, elliptic, 0-5-2 cm. long, 0-5-1-1 cm. wide, obtuse or acute. Intermediate sepal linear, (0-7-)l-6-l-8 cm. long, joined to the petals to form an open but deeply concave, transversely boat-shaped or sometimes almost hemispherical hood, 0-7-1-5 cm. long, 0-8-1-8 cm. wide (not opened out flat), mostly pinkish or greenish with mauve lines and often a yellow pattern at the back; lateral sepals elliptic or almost semicircular, 0-85-1-7 cm. long, 5-5-10 mm. wide, obliquely apiculate at the apex, joined for about a quarter to a third of their length, bearing small sacs 0-3-0-5 mm. long. Petals oblong-elliptic, ovate or semicircular, narrowed at both ends, 0-7-1-7 cm. long, 0-7-1-1 cm. wide. Lip mostly yellowish, ± 7-5-10 mm. long, with claw sharply bent back on itself near base and there dilated into a densely papillate appendage, which is typically large, reniform and apically emarginate, 2-5-3-5 mm. long, 4 mm. wide, but varying to deeply 2-lobed; claw terminating in a spathulate, elliptic or almost circular limb bearing a papillate crest or spur. Fig. 39/1, p. 220. var. katangensis

Flowers mostly large.

Tanganyika. Buha District: Mkalinzi [Kalinzi], Deo. 1956, Procter 611!; Ufipa District: Kirambo, Jan. 1964, Richards 18729!

Distr. T4; Congo Republic, Zambia

Hab. Dense Brachystegia woodland, in loam in shade by lake-edge, also on poorly drained soil in pockets on quartzite ridges; 1500-2000 m.

Note. At first sight Richards 18729 would appear to be totally distinct from typical D. katangensis , the hood being very small, only 7-8 mm., and the basal lip-appendage deeply divided. Examination of all the available material shows that much material from NE. Zambia has the lip appendage deeply divided. Further work may show that two subspecies can be recognized. Procter 611 has a typical appendage but both Tanganyika specimens have abnormally small flowers. A small-flowered variant, var. minor Verde ., occurs in Zambia.