264 INTRODUCTION TO BOTANY 
In moist and shady places protonema may grow until great 
mats are formed upon the soil, old logs, etc., and in these 
places the alga-like protonema may live for several years. 
At times some of the protonemal cells produce outgrowths 
which divide by oblique walls and form buds (fig. 203, B and 6). 
The buds may become dormant and lie for months or even 
longer, and then continue to grow; or there may be no resting 
period. When they grow, the outermost cells produce leaves, 
the central ones become the stem, and from the lower ones the 
root-like hairs (rhizoids) grow. The rhizoids descend into the 
soil or other substance below the plant, and the leaves and 
stem rise into the air. The buds, therefore, which grow from 
the protonema are the beginnings of the leafy moss plant. 
250. Sexual and asexual reproduction in the moss. At the 
tip of the stem of the leafy plant, more or less inclosed by 
the leaves, the sex organs of the moss develop. These are of 
two kinds, and with them there are usually taller sterile fila- 
ments, which bear chlorophyll and may serve to protect the 
sex organs. In some kinds of mosses only one kind of sex 
organ is borne on a single plant, while in other kinds both 
are produced on the same plant at the same time. Neither 
can be studied without magnification, although the male sex 
organs may sometimes be detected without a lens. 
The archeyonium, the female sex organ, is similar in func- 
tion to the odgonium in Vaucheria. It is flask-like and has 
an elongated neck (fig. 204, D). In the swollen part of the 
archegonium the egg is formed. When the egg is mature, the 
central cells of the neck become gelatinous, and the end of 
the neck opens so that there is a passageway through the neck 
down to the egg. The male sex organ, the antheridiinn, is 
club-shaped (fig. 204, 4), being attached by its smaller end 
to the tip of the plant stem. When the antheridium opens, 
its thousands of sperms are set free. The sperms swim with 
great activity, and some of them may come into the vicinity 
of the neck of the archegonium. One or more make their way 
down through the gelatinous neck of the archegonium to the 
