THE MOSS WORLD. 
369 
which thus resembles a rasp. In form the cells exhibit much 
variation, but they are referable to two types, 
1. Parenchymatous when the ends are flattened, and we get 
a quadrate or hexagonal areolation as in Funaria ; and some- 
times the cell walls are so thickened by internal deposit that 
their cavities appear like dots, as we see in Grrimmia, Ortho- 
trichum, Andresea, etc. 
2. Prosenchymatous when the transverse walls of the cells 
are oblique, so that the cells have pointed ends, as in Bryum, 
Hypnum, &c. 
According to the quantity and tint of the chlorophyl con- 
tained in the cells will be the shade of colour of the plants ; 
this is usually more or less green, but in Andreaea it is choco- 
late-brown or black, and some mosses are not unfrequently 
tinged with rosy purple or brown. The cells forming the leaf 
base are often of a different form from the upper cells, and when 
the leaves are closely imbricated they are thinner and usually 
empty ; but those situated at the outer angles are sometimes 
very different from the rest, and then these alar cells become 
of value in the distinction of species and even of genera, as in 
Dicranum, for instance. 
Reproductive System. 
If we hunt up Funaria in December we shall find that 
instead of the long-stalked capsules the plants bear little 
rosettes of leaves, which are truly the flowers, and contain in 
their centre those reproductive organs, which even more clearly 
than stamens and pistils are necessary for the formation of fruit. 
The little starry heads at the end of the young lateral shoots 
are the male flowers, and by dissecting away the enveloping 
perigonial leaves in water we arrive at a cluster of fine- 
jointed threads or paraphyses, among which are little sausage- 
shaped bodies, the antheridia, which at maturity give out a 
fluid containing excessively minute spiral threads, the sperma- 
tozoids ; and it is to preserve the vitality of these that para- 
physes are present, so as to keep up a certain amount of mois- 
ture ; for the paraphyses are wanting in the closed bud-like 
flowers of Hypnum. If we look among the leaves terminating 
the stem we shall find similar female flowers also containing 
paraphyses, and longer and more slender bodies, archegonia, 
which are traversed by a fine channel, and open at maturity by 
a trumpet-shaped orifice, into which the spermatozoids pass, 
and reaching the germ cell in the base of the archegonium, 
this becomes fertilized and at once begins to develop into 
fruit. 
In some mosses these two kinds of organs exist in one flower, 
