- 81- 
stand the test of validity, but it is so brief and uncertain that one can hardly 
regard it satisfactory. Several new genera are placed under the Lecidea- 
ceae on page 77 and under the P eltopho 7 'aceae on page 174. The omission 
of the former family on the latter page is of course an oversight. 
While holding the opinion that the lichen is a fungus, Dr. Clements seems 
to have based the genera Chloropeltis , Cyanobaeis and Cystolobis upon 
characters of the algae in relationship with which the lichens involved 
grow. This appears hardly consistent, since he points out no morphological 
differentiation of each genus due to the host. Chloropeltis replaces 
Peltidea without any explanation, and whatever name is used, the genus 
should rest upon the peculiarities in development of the apothecium as 
worked out by Fiinfstiick, ' not upon the algae. 
Changes in form of names of lichen genera, fortunately are not numer- 
ous. Peltige 7 'a is changed to Peltopho 7 'a and Peltigei'aceae to Peltophor- 
for reasons that are not stated, but which may appear in a careful 
study of the origin of the names. The on endings are all changed to iim, 
which is better form, though there is doubt whether the 'change from the 
original form is warranted. Theloschistes is retained, though the original 
Teloschistes is correct and expresses exactly a diagnostic character of the 
genus not expressed by Theloschistes, which has a quite different meaning. 
The writer can not pass minutely upon the merits of the portions of 
the keys dealing with lichens, for he has had no occasion to put them to 
severe test himself or in the hands of students. However, in the nature of 
the case, being based upon the recent work of Dr. Zahlbruckner, they should 
be better than portions based upon Saccardo. In general they appear 
good with such examination as could be made by running through them 
somewhat carefully. 
The expression “ parasitic on algae” is commonly used in the keys and 
is misleading in a number of ways. Dr. Clements gives no definition of the 
term “parasitic” in the glossary. In his Plant Physiology and Ecology,”- 
page 104, we find the following : — “ The type of parasitism in which the 
presence of the parasite benefits the host-plant in some measure is 
commonly distinguished as symbiosis or mutualism.” This view of both 
parasitism and symbiosis is unusual, but admits of his use of the expression, 
“parasitic on algae.” Nowhere in the keys does one get any adequate 
statement of the relationship of the lichen to a substratum, and this omis- 
1 Fiinfstiick, Moritz. Beitragfe zur Entwickelungsgeschichte der Lichenen. 1 — 20. pi. 
3 and 4. Berlin. Gebriider Borntraeger, J8b4. Reprint from Jahrb. K. Bot. Gart. u. 
Bot. Mus. Berlin. 3: 1884. 
2. Clements, F. E. Plant Physiology and Ecology. I-XV. 1-315 f. 1-125. New York. 
Henry Holt and Company, 1907. 
