290 ORCHIDS OF THE SIKKIM-HIMALAYA. 
The spur is in this species distinct'y divided into two unequal antero-posterior 
chambers for a short space near the mouth by a horizontal plate which (as shown 
in figs. 3 and 4) proceeds from the anterior callus. The spur is a!so constricted below 
this plate, and about its middle, by the calli which project from its back and front walls 
and almost divide it into an upper and a lower section. In these respects this is not 
a true Saccolabium, as that genus is understood in this work, there being in the 
spur of Saccolabium neither callus nor septum. Мог is it a true Cleisostoma, the spur of 
which genus is occluded not only by antero-posterior calli, but sometimes also by a plate 
proceeding from the back wall. Neither is it a Sarcanthus, in which genus there is, 
besides calli, a vertical antero-posterior septum dividing the spur into two lateral 
chambers. In fact there is as much justification for making this the type of a new 
genus as there was for the formation of Cleisostoma as a genus; for the presence of 
a horizontal p'ate (forming a small chamber) on the anterior wall is of as much 
importance as the presence of a plate on the posterior wall. But, in our opinion, 
there are already too many genera in this neighbourhood. We therefore leave this 
plant in Saccolabium, where it is placed by Dr. Reichenbach and Sir Joseph Hooker, 
being in entire agreement with the remark of the latter distinguished botanist (FI. 
Br. Ind. VI, pp. 66, 71) that, but for the undesirable dislocation of synonymy which 
would result, it would be better to reduce both the genera Cleisostoma and Sarcanthus 
to Saccolabium, 
Prate 306.—Saccolabium trichromum, Reichb. fil. Part of a plant, of natural size. Fig. 1 a flower, 
2 stalked ovary, column with anther іп situ, and lip, 3 longitudinal section of column and spur, 
4 transverse section of spur above the middle, 5 lower surface of empty anther, 6 pollinia i» site 
on the apex of the column, 7 the same removed; a4 enlarged. 
` 52. Cleisostoma, Blume. 
Epiphytes without pseudo-bulbs. Stems more or less elongated, leafy. Leaves 
coriaceous or fleshy, flat or semi-terete. Inflorescence leaf-opposed, racemose or paniculate. 
Sepals and petals adnate to the column, spreading, sub-equal. Zip sessile on the foot- 
less column, the base with a large saccate or infundibuliform spur, sometimes dilated 
at the apex, its cavity more or less closed by two calli the posterior of which is often 
bifid, and sometimes also by a dorsal scale, but never by a septum; the lateral lobes 
small or absent; the apical lobe thickened, concave. Column short, thick, with no foot. 
Anther depressed; pollinia two, often bifid; caudicle single. Species about 40; Eastern 
Asiatic and Australian. : | 
Cavity of spur occluded by two calli, the dorsal ome divided at the 
apex into two scale-like plates. 
Leaves semi-terete, channelled in front, their apices acute and 
Us э... (Ox os. М, жй aS жан 
Torres flat but E ۰ 
Spur widely saccate, not dilated at the apex; apical lobe 
of lip triangular-hastate, its narrow and bifid; apices 
of leaves acute. . v7. к Ж U opa. 
Sod Spur infundibuliform, dilated iud ыйа " the Ga ; apical 
T cp lobe of lip thick, triangular-ovate, acute, entire; apices of 
rg leaves broad, obliquely bifid . . . . . . . . . . « & C. apicatum. 
