216 DR. M. T. MASTERS ON THE MORPHOLOGY 
it commonly happens that the membranous apex of the sheath 
becomes cleft into two divisions, in which case the resemblance 
to a needle-shaped leaf with two membranous adnate stipules is 
very marked. In some species of the allied genus Hypolena the 
membranous edge of the sheath is regularly cut up into a number 
of hair-like Jacinie, similar to those constituting the “ ligula” of 
Saccharum, &e. 
In many of the species, and most markedly so in R. venustulus, 
R. laniger, and R. scoparius, the sheaths enclose an inner oblong 
scale, which is marked on one surface with two prominent hairy 
ribs. This scale is placed at the bifurcation of the culm or branch, 
and apparently serves as a kind of cushion or pad, the culm or 
branch fitting into the groove between the two projecting 
“ cost.” 
Bracts.—The bracts or scales of the inflorescence do not differ 
materially from the other foliar organs just mentioned ; ordinarily 
they are shorter and do not completely encircle the axis as the 
lower ones do. The lowermost or outermost bract is sometimes 
different from the rest, having then more of the character of the 
. true culm-sheaths ; in this case it may be compared to the spathe 
of Arads, or the outer glume of Grasses. In many instances the 
bract next above the lowermost, and which is pressed up against 
the axis, has the oblong form, and the two woolly ribs, such as 
have just been mentioned as occurring in the forks of the branches 
in R. venustulus and many other species. Pressure here evidently 
determines the presence of these two ribs, as probably also in the 
instance of the inner palea of Grasses, which occupies a precisely 
similar position with reference to the axis. Other illustrations of 
the same kind may be noticed in Iris, in Philydrum, &c., in those 
bracts which are pressed between the axis and the flower-bud. 
The bracts are sometimes all about of the same size and form, 
while at others the lower ones are the smallest, and gradually 
increase upwards till they approach the top of, the spikelet, when 
they again diminish in size; in the latter situation also they often 
lose the mucro or awn which the lower scales are for the most 
part provided with*. 
Good specific characters are afforded by the comparative length 
of the bracts and of the florets they subtend, a difference which 
may be of physiological importance with reference to the facilities 
* The observer cannot fail to be struck with the foliaceous awn projecting 
from the back of the inner involucral scale of Pieris echioides just below the 
apex, exactly as in the sheaths of Restiaces or in the pale; of Grasses. 
