CONTRIBUTIONS TO BOTANY. 
233 
species of the genus, may be regarded as a stunted branchlet 
in which the abortive leaves are reduced to the condition of mi- 
nute bracts, each of its axils being furnished with a very short 
umbellated panicle. 
30. Clambus. 
This genus was founded by me, more than twelve years ago, 
upon a Mexican plant, collected by Ruiz and Pavon, its general 
characters being sketched, two years since, in my synopsis 
{supra, p. 17). It belongs to the CissampelidecB, and differs 
from Cissampelos in its very different habit, its inflorescence, 
and the presence of six sepals and six scale-like petals in the 
male flower : in this latter respect it approaches Pericampylus 
and Pseliwn; but its anthers are combined in a peltate disk 
supported on a slender filament, as in Cissampelos. It offers 
some analogy towards Stephania •, it has the same number of 
sepals, but double the number of petals, a different kind of 
inflorescence, and a dissimilar habit. The female plant is un- 
known. The genus differs from all others of the Cissampelidece 
in its leaves not being peltate, and therefore not palmatinerved, 
the nerves being all imparipinnate as w'e find them in Pycnar- 
rhena, Penianthus, and some species of Hypserpa : the leaves are 
supported upon very short petioles, and are ovate or elliptic, 
with about eight pairs of alternately diverging nerves ; they are 
very reticulated above, glabrous on both sides, but opakely white 
beneath : this cretaceous appearance, when viewed under a lens, 
is found to consist of a prominent network of white and ex- 
tremely minute crossing fibres, like a spider’s web, which fills 
the areoles of the ordinary venous reticulations. The inflores- 
cence is axillary, upon an elongated, very slender rachis longer 
than the leaf ; its alternate branches, bracteolated at base, are 
dichotomously divided, the branches bearing many alternate 
pedicels, bracteolated at base, and spicately arranged. 
Clambus, nob. ; — Flores dioici. Masc. Sepala 6, biseriata, sub- 
aequalia, alternatim pautulo angustiora, oblonga, petaloidea, 
nervo longitudinal! signata, patentia, sestivatione imbricata. 
Petala 6, subbiseriata, sequalia, sepalis dimidio breviora, 
lineari-oblonga, apice emarginata, crasso-carnosa. Stamen 
unicum, centrale ; filamentum tenue, sepalis paulo brevius ; 
anthera peltata, 3-locularis, aunuliformis, circa connectivum 
peltiforme aflixa, loculis emarginatis, transversim bilocellatis, 
extus horizontaliter 2-valvatim dehiscentibus. — FI. fcem. et 
fructus ignoti. 
Frutex Mexicanus, forsan volubilis, ylaberrimus ; folia alterna, 
VOL. III. 2 H 
