583 
the thallus or adventitious branches developing endogenously 
from the “ gonidial” (algal) layer of the thallus. They possess a 
gonidial zone which enables them to, function as the thallus proper; 
indeed in some C/adoma species the thallus is rudimentary or 
wholly wanting, in which case the assimilating function devolves 
wholly upon the podetia. Sometimes they continue to grow for 
centuries without bearing apothecia or pycnidia, sometimes they 
bear both and in addition soredia. In fact, they develop, grow 
and function as the thallus proper. 
In Part II. Reinke discusses the position of lichens in the vege- 
table kingdom. The author places lichens as an independent 
branch of the plant kingdom, having a special phylogeny. His 
idea is essentially as follows: In the beginning lichens originated 
_ through the association of a fungus and an alga in which the 
_ fungus played the part of a true parasite, hence the symbiosis was 
not yet mutualistic. Through natural selection or some other 
factor the symbionts developed into a morphological unit, for ex- 
ample, Collema thallus. Out of this first lichen (Co//ema) other 
_ species have branched off. Lichens belong neither to the algz nor 
to fungi. The author considers a lichen as perfect a morphologi- | 
cal unit as a tree.. He suggests that it may be possible to separ- 
ate the green and colorless portions of higher plants. (The writer 
would here state that theoretically chloroplastids of phanerogams — 
must be looked upon as much modified alge, or at least as chlo- 
rophyll bearing and CO, assimilating living units.) The true re- 
productive organs of the lichen are the soredia, since they alone 
Possess the structures capable of producing a new lichen. The 
Spores cannot develop a new lichen until they can develop with 
the essential alga. Hyphz and gonidia (alga) have the same re- _ . 
lation to each other as the green and colorless cells in Riccia 
and Marchantia. Therefore, lichens should not be placed sub- 
ordinate to fungi, as is almost universally done now. ‘ ; 
In conclusion, the writer would express it as his opinion that — 
most modern lichenologists agree with the author as to the lichen __ 
nature. The lichen structure is certainly more or less of a mor- 
y phological unit. In the ages to come the lichens may be placed fe 
as a separate class. By that time they may have become more — 
deci idedly eee 5 as units. “Our tees seuags De of their 
