286 CXXXIII. ORCHIDEE (BROWN). [ Disa. 
19. D. aperta, A. E Brown. Plant 15-18 in. high, glabrous. 
Stem with 4-6 oblong, acute, coriaceous leaves about as long as the 
internodes, erect and more or less embracing the stem, 14—24 in. long, 
including the sheathing portion, 24-6 lin. broad. Spikes 7-9 in. long, 
1} in. diameter, lax, elongating. Bracts 4—7 lin. long, 2—3 lin. broad, ovate 
or ovate-lanceolate, acuminate. Dorsal sepal reflexed at a right angle to 
the ovary, 4 lin. long, 2 lin. broad, galeate, rather abruptly contracted at 
the middle of the back intoa straight, compressed, very obtuse spur 14-2 
lin. long, ?-1 lin. broad. Lateral sepals directed forwards at nearly a. 
right angle to the ovary, 44-5 lin. long, 24-3 lin. broad, obliquely 
elliptic-oblong, obtuse with a compressed dorsal mucro at the apex. 
Petals 3 lin. long; basal half 2 lin. broad, narrow oblong ; apical half 
1-1} lin. broad, ovately semisagittate, acute. Lip directed in a line 
with the ovary, 3-34 lin. long with a linear claw 2 lin. long, and an 
oblong, obtuse blade, 2—24 lin. long, 1 lin. broad, cuneate at the base, 
longitudinally folded down the middle. Anther horizontal, 2 lin. long. 
oe a short, acutely bifid, very slightly folded between the anther- 
cells, 
Mozamb. Dist. British Central Africa: Fwambo, S. of Lake Tanganyika, 
Carson, 51! 
20. D. hamatopetala, Rendle in Trans. Linn. Soc. ser. 2, iv. +7, 
pl. 7, figs. 4-6. Plant 6-18 in. high, glabrous. Leaves linear-filiform, 
often withered or burnt off at the time of flowering, leaving a tuft 
of their remains at the base of the stem. Flowering stem slender, 
with 6-12 membranous, distant, acuminate sheaths, lower about an 
inch long, upper smaller. Raceme laxly 1-7-flowered. Bracts shorter 
than the ovaries, 3-6 lin. long, 14-3} lin. broad, ovate, acute, 
terminated by a fine awn-like point. Flowers rather large, blue- 
Dorsal sepal erect, 7-9 lin. long, 4-5 lin. broad, helmet-shaped, with a 
stout, ascending, obtuse spur, 24 lin. long, 1-1} lin. thick. Lateral 
sepals spreading and deflexed, 6—9 lin. long, 24-4 lin. broad, oblong, 
obtuse, concave. Petals 4-5 lin. high, strongly curved forwards; base 
with a broad semicordate auricle, 14-2 lin. long, 1}-14 lin. broad ; 
middle part linear, 4-2 lin. broad; apical part dilated to 14-2 lin. 
broad, somewhat hatchet-shaped, bifid or trifid, the two principal teeth 
being 3-1} lin. long, the third, when present, much shorter. Lip 6-9 
lin. long, 3—4 lin. broad, oblong in outline; margins deeply cut into à 
fringe of simple linear-clavate or filiform-clavate processes. Antber 
horizontal, 11-14 lin. long, oblong. Rostellum trifid; middle lobe 
slightly folded between the anther-cells and emarginate at the apex. 
Mozamb. Dist. German East Africa: Higher plateau, N. of Lake Nyasa, 
Thomson! British Central Africa: Nyasaland; between Lake Tanganyika and Lake 
Nyasa, Johnston ! between Kondowe and Karonga, 2000-6000 ft., Whyte, 845! 
Mt. Malosa, 4000-6000 ft., Whyte! Zomba, 6000-7000 ft., Kirk ! Whyte! Many, 
6000 ft., Whyte, 36! 186! and 199! Mlanji Plateau, Johnston! Litshengu Plateau, 
6800 ft., MeClounie, 10! and without precise locality, Buchanan, 1016! 
There are also specimens at Kew, collected by Zhomson, on the higher glaten 
N. of Lake Nyasa, which I cannot distinguish structurally from D. hamatopetala- 
but they have very much smaller flowers, the dorsal sepals being 3} lin. long, 2 wc 
