218 
CONTRIBUTIONS TO BOTANY. 
the entire aspect of the plant proclaims that it cannot belong to 
that genus, as does that of Clambus for a similar reason. Its slender 
branches, with very distant axils, are furnished with long, patent, 
simple hairs, which I have never seen in any species of Stephania ; 
its leaves are larger, and, though peltate, are pilose on both sides, 
and their margins are furnished with a strong marginal nerve, 
which is indented into several rounded lobes or large crenatures, 
and they are supported upon unusually long and slender petioles. 
The inflorescence, instead of being, as in Stephania, a compound 
umbel rarely exceeding an inch or two in length, is here a very 
slender pendent raceme a foot and a half long, with numerous 
distant, short, alternate branches, which are again and again 
alternately divided : in all these respects the general habit of the 
j)lant is moi’e in harmony with some species of Cyclea. The 
flowers are very minute, pedicellated, with six oblong, subacute 
sepals in two series, imbricated in aestivation, three small, ovate, 
erect petals, and a central stamen almost concealed by the pe- 
tals. It is, however, in the structure of the stamen that this 
genus differs essentially from Stephania : in the latter genus the 
anther has three or six cells, connate so as to form a ring, affixed 
on the margin of a peltate disciform connective, which is sup- 
ported on the central filament ; these cells always burst bival- 
vately by a crenated horizontal line of sutures. In Perichasma 
the anther has no connective, is comparatively large, completely 
globular, simply 1-celled, and dehisces by a somewhat small 
apical opercular valve, which is supported by a columella-like 
extension of the filament (or placentoid of M. Chatin), round 
which the grains of pollen are secreted ; the wall of the globular 
cell consists of a finely reticulated membrane (apparently defi- 
cient of the usual inner lining or endothecium), is very delicate 
in texture, without the slightest vestige of any dissepiment 
or nervure, its three indented furrows being due to the external 
pressure of the petals which embrace it in the bud. This 
organization of the anther is without any parallel in the Meni- 
spermacece, and reminds us of the opercular theca of some of the 
mosses. 
The generic name is derived from Trept, circumcirca, 
hiatus, in allusion to the feature just mentioned. I have placed 
it among the Cissampelidece, but I am not certain that this is its 
proper place. 
Perichasma, nob. — Flores dioici. Masc. Sepala 6, biserialia, 
quorum 3 interiora paululo longiora,oblonga, submembranacea, 
demum expansa. Petala 3, dirnidio breviora, orbicularia, 
carnosula, margine membranaceo, erecta, sepalis exterioribus 
opposita. Stamen unicum, centrale y filamentum tenue, petalis 
