-83- 
are made to include subdivisions containing in the aggregate about 2000 
described species. He credits all of these with possessing a perithecium 
and states that in the A7 thoniae the perithecium is without an exciple. It 
may be doubted whether any of the fruits in the Graphidaceae should be 
called perithecia, and a perithecium without an exciple is scarcely a perithe- 
cium at all. It is by no means certain what should be done with Chiodecton- 
and Dirina-W^e. plants, but it appears to the writer that A r//iom‘a-\ike plants 
might better be separated on the basis of fruit- character. Lack of space 
forbids adequate discussion of family limitations in the Parmeliaceae and 
Physciaceae, but it seems that the Teloschistaceae and the Caloplacaceae 
'with their characteristic chemical relations and spore structure might better 
be kept separate from the Physciaceae. 
It has been impossible thus far for most lichenists, and other botanists as 
well, to relieve themselves of tradition sufficiently to see that the dual-hypo- 
thesis theory and the consortism theory of lichens are alike untenable, and 
of the few who have concluded that the lichen is after all a fungus pure and 
simple only two. Dr. C. E. Bessey^ and Dr. Clements, have attempted to 
devise ways of distributing the lichens to the exclusion of the class Licheties. 
Bare distribution without statement of reasons why lichens should be thus 
distributed is not very convincing to botanists who think that these plants 
should still be retained in a distinct group, but the writer is convinced that 
anyone who goes very deeply into the study of lichens, at the same time 
freeing himself as much as possible from the influence of tradition, must 
finally conclude that the distribution of lichens in some such manner as that 
proposed by Dr. Clements is the only proper treatment of those plants and 
that the only question that remains is the manner of distribution. We can 
not hope for a very satisfactory solution until further studies of Ascomycetes 
gives us a more thorough knowledge of the relationships of these plants, but 
Dr. Clements’ treatment furnishes a working basis and appears to be better 
than retaining the artificial group Lichenes. In this lies the great value of 
Dr. Clements’ work so far as the lichens are concerned. 
Another commendable feature of the work is the application of the 
terminology of mycology to lichens. Since the close relationship of these 
plants to other fungi seems apparent, much of the antiquated and objection- 
able terminology of lichenology may well be dispensed with. The excellent 
glossary and the comparatively complete index of genera of fungi are in 
themselves very helpful. 
It will readily be seen that much of the matter which the writer finds 
objectionable will not interfere with the use of the keys, which seem to be 
workable in spite of the faults pointed out. We trust that a revision may 
appear in due time, which will obviate certain faults and add considerably to 
the value of the work. In the meantime, the volume will be found help- 
ful to those who work on lichens or other fungi. 
Miami University, Oxford, Ohio. 
1. Bessey, C. E. A Synopsis of Plant Phyla. University of Nebraska Studies 74. 
1-99. 1907. 
