54 TrWEHRl. 
Mt. Ray-wa, n. 2 131. Nearest to S. produ6la ) but much 
less and more laxly branched, with more distant leaves, 
and quite different fruit spikes, which are only 1-2 Li. 
long. The habit is flaccid, and it spreads quite flat on 
the ground or other surface that it may be growing on. 
The variety is a lax form (my n. 181 9) also from the 
Kaieteur Fall region ; a region abounding in ravines 
and great fissures between rocks, in which Selaginellas 
are plentiful. In this and the two preceding the bra6ls 
are of two kinds, larger and smaller, in which the order 
observed in the leaves is reversed, the smaller ones fol- 
lowing on the larger leaves, and the larger on the smaller 
leaves. 
General distribution — Endemic. 
Genus II — Isoetes, Linn. 
Leaves herbaceous, from a few inches to a foot or more high, 
springing in a dense rosette from a thickened corn-like rootstock, acau- 
lescent, the expanded base clasping, tapering thence upwards to th e 
acuminate, often convolute, point. Sporangia contained in the axils of 
the leaves, partly immersed in the interior of the base, the maerospo- 
rangia in the inferior and the microsporangia in the superior ones. 
Macrospores spherical ; microspores 3-gonal. 
Thtise, the Quillworts of Britain, are herbaceous bog 
or aquatic plants, with numerous leaves, appressed 
together at their expanded bases, from whence they 
taper rapidly to the much reduced point, the height 
varying with the different species, forming a dense 
rosette. Sporangia are concealed in the clasping 
bases, and must be sought for by removing the 
leaves. I have seen no Guiana species,, but it is pos- 
sible the genus may be represented in the higher regions 
as it is in the countries around, for which reason I 
include' it. There are about fifty species. They chiefly 
