LIFE HISTORY 
329 
forming a tangled mass called the protonema (pro-to-ne'ma: 
Greek, protos, first; nema, thread). These threads pro¬ 
duce buds from which leafy moss plants grow. The latter 
produce gametes (reproductive cells which unite to form a 
new organism) and so these moss plants are called gameto- 
phytes (gamete plants). 
The gametes are of two kinds, eggs (large non-motile 
cells) and sperms (motile cells). The egg cells are produced 
in special vase-shaped organs called archegonia (ar-ke-go'ni-a), 
and the sperm cells in other organs called antheridia. When 
moss plants are repro¬ 
ducing, both of the re¬ 
productive organs are 
found surrounded by 
sterile hairs at the top 
of the stems. Some 
mosses have both an¬ 
theridia and archegonia 
on the same plant, while 
other mosses have only 
one kind on each plant. 
The moss plant which 
bears the antheridia re¬ 
mains short and has on the top a rosette of leaves, in the 
center of which is the sex organ. The plant which bears 
archegonia usually grows tall after the egg cells have been 
fertilized. 
Many sperms come from each of the antheridia. These 
move by the use of cilia when water is present, a film of 
dew being sufficient. The female moss plant has on its 
upper end one or more archegonia, each of which contains 
an egg cell. When the egg is ripe or ready To be fertilized, 
sperms may swim to it if water is present. A sperm enters 
the archegonium and fuses with the egg cell, thus forming a 
sexual cell, known as the fertilized egg cell. 
Figure 299 . 
Diagram of Life History 
of Moss. 
