—82— 
which may serve as gonidia, they perish. But if proper Algae are encoun 
tered, then the hyphse begin to grow vigorously and form a network of 
branches enveloping them. This first thin layer of hyphse, called the hypo- 
thallus , remains a prominent feature of some adult lichens. With the 
Fig. 7. The same. Vertical section of a spermagone, 
magnified about 200 diameters. 
Fig. 8. The same. Sterigmata (St.) and spermatia 
(SE.), magnified about 1,500 diameters. (Original). 
majority, however, as with Parmelia, it serves chiefly as a groundwork 
from which the thallus proper is developed, although it may persist to some 
extent in the rhizoids. 
The spermagones (Fig. 7. and 
Sg., Fig. 2) are, as we have seen, 
flask-shaped cavities, opening by 
a minute pore. Ihto the cavity 
projectdnnumerable short hyphal 
branches, called sterigmata, (St., 
Fig. 9. Acolium tigillare. Slightly magnified. Fig. 8), which produce as out- 
(Original). growths exceedingly minute bod- 
ies, termed spermatia (Sm.). These, when ripe separate readily from the 
sterigmata, and under the influence of moisture are extruded through the 
pore in a mass of jelly. 
The function of the sper- 
matia is .somewhat ob- 
scure, their minuteness 
rendering investigation 
of them particularly diffi- 
cult. In certain lichens 
there is evidence that 
they perform a service 
analagous to that of pol- 
len — that is to say, they 
are male elements that 
fertilize a female cell, 
Fig. 10. Peltigera canina. Natural size. (After Kerner.) 
