TAXONOMY 
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evolved type of bryophytes. Examples: Polytrichum , F unaria , 
Hypnum, and Mnium. 
Life History of Poly trichum Commune (A Typical True Moss). — 
Polytrichum commune is quite common in woods, forming a carpet- 
like covering on the ground beneath tall tree canopies. It is dioe- 
cious, the plants being of two kinds, male and female. 
Beginning with a spore which has fallen to the damp soil, we note its 
beginning of growth (germination) as a green filamentous body 
called a protonema. This protonema soon becomes branched, giving 
Fig. hi. — Protonemata of a moss bearing young gametophyte buds. (Gager.) 
rise to hair-like outgrowths from its lower portion called rhizoids 
and lateral buds above these which grow into leafy stems commonly 
known as “moss plants.” At the tips of some of these leafy stems 
antheridia (male sexual organs) are formed while on others arche- 
gonia (female sexual organs) are formed. These organs are sur- 
rounded at the tips by delicate hairy processes called paraphyses 
as well as leaves for protection. The antheridia bear the anthero- 
zoids, the archegonia, the eggs or ova, as in the liverworts. When 
an abundance of moisture is present the antherozoids are liberated 
from the antheridia, swim through the water to an archegonium 
