198 MR. H. N. RIDLEY ON A 
2-3 inequalia, ovata, acuta, obliqua. Scapus debilis inferne nudus, 
bracteis paucis exceptis. Flores parvi, patentes, haud resupinati, 
flavi. Bracteæ breves, lanceolate, acute. Sepalum posticum 
longiusculum, oblongum, lanceolatum, obtusum; lateralia bre- 
viora, ovata, falcata, labello supposita. Petala obliqua, ovata, 
lanceolata. Labellum sepalis brevius, obovatum, emarginatum, 
pulvina pubescente purpurascente in medio. Gynostemium sub- 
teres, gracile, arcuatum, superne attenuatum. Anthera terminalis 
filamento brevi, rostello adnata, loculi valde discreti, lateraliter 
mox dehiscentes.  Pollinia 4, exappendiculata, elliptica, curva, 
iransversa, ceracea, flava. Stigma tenue, profunde concavum. 
Rostellum latere tenue obtriangulare, apice lato obscure sinuato, 
anthers adnatum et celans. Fructus ignotus. 
ORESTIA ELEGANS, n. sp. (Plate VI.) 
Caules 3-unciales, graciles. Folia 2-3 tenuia marginibus 
crispis, maximum 3 uncias longum 1% unciam latum. Scapus 6- 
uncialis, angulatus ; bracteis j*5-uncialibus, ovatis, acuminatis, 
paucis, inferne dissitis. Racemus multiflorus, laxiusculus. 
Bractee florales lanceolat®, acute. Pedicelli suberecti, j-unci- 
ales. Flores flavi, callo in disco labelli purpurascente. 
Island of St. Thomas, West Africa, at 1200 m. Coll. Mollec. 
This plant is one of no little interest on account of the re- 
markable structure of the column, which differs in arrangement 
of parts from that of any genus known to me, so that it is very 
difficult to establish clearly its relations with other forms. 
The habit, as stated above, is just that of Microstylis stelido- 
stachya. It has a stem of a few inches in height covered with 
thin whitish sheaths, and terminated by a tuft of oval leaves, 
from the centre of which rises a slender scape terminated by a 
lax raceme of little flowers. The sepals are dissimilar, the upper 
ones narrower than the lower, which are ovate and falcate, 
lying under the round lip, which they surpass in length. The 
petals are narrower than the sepals, ovate, lanceolate, and slightly 
curved. The lip, which is flat, has in its centre a small round 
pubescent cushion, over which the slender column bends. The 
` column is cylindrical at the base, gradually tapering towards the 
anther, where it is dilated into a kind of hammer-head. On the 
front of this is a thin-walled tube forming the stigma, above which 
is a thin, broad, obtriangular portion which, I believe, to repre- 
sent the rostellum. From in front the anther is almost entirely 
