1904] FINK—A LICHEN SOCIETY ans 
VI. ORIGIN OF THE SOCIETY. 
Just how each species arrived at the spot or when it came is not 
easily stated. It is supposed that fragments of lichens carried in 
the wind fall in places favorable for growth.! Few of the lichens of 
the society are conspicuously sorediate, but it is probable that nearly 
all of them arrived at the spot from some place near at hand, through 
purely vegetative dissemination. In this way the species may even 
Fic, 
3-—Somewhat shaded and disintegrated riprap blocks near ground on north 
Side on 
» “8 extension, with Cladonia fimbriata scattered throughout the field, C. /urcata 
at Paid le 
_ RC eis Statella vestita in the crevice at the forefront, and a few white thalli of 
mphiloma-like. plant 
wt eraved from stations quite remote from their present position. 
account the statements given above as to the scarcity 
the circle of 300™ in diameter and immediately sur- 
Society, this supposition seems quite probable, at least 
Pecies 8 ner of the species. Yet the inconspicuous, crustose 
Thus the Biator come from a few Kansan bowlders recently removed. 
a and the Bacidia may have reached their present 
' Per 
IRCE, G. toa 
Calif, Acad. Sci cl, th og oe of the association of alga and fungus in lichens. Proc. 
