1887. | BOTANICAL GAZETTE. 143 
CURRENT LITERATURE. 
An Introduction to the Study of Lichens. By Henry Willey. 72 pp. and 
10 plates. Printed for the author, New Bedford, Mass. 
No more competent lichenologist could have been found in this coun- 
try, since the death of Professor Tuckerman, to prepare this introduc~ 
tion to the study of lichens. It is a group beset with great difficulties, 
and hence discouragements, for the beginner, and this must account, to 
some extent, for the limited number of lichen students in this country: 
Mr. Willey has thus done good work in exactly the direction it was 
needed, and under the guidance and stimulus of this simple introduction 
the way into thié \department has been made as easy as was possible: 
There are six chapters, with the following subjects: On collecting and 
mounting lichens; The lichen, its structure and organs; The distri- 
bution, etc., of North American lichens; The history of lichens; 
Helps to the study of lichens; and Arrangement of North American 
lichens. Then follows a supplement giving a list ot the names of all 
published lichens. The ten plates display the structures of the thallus, 
gonidia, apothecia, spermagones, and pycnides, and end with illustrations 
of the spores of all the seventy-six genera. We mistake the effect of this 
pamphlet greatly if it does not very much stimulate the study of this 
difficult and interesting group in this country. It can be procured from 
the author for $1. 
Die natiirlichen Pflanzenfamilien, nebst ihren Gattungen und wichtigeren 
rten insbesondere den Nutzpflanzen, bearbeitet unter Mitwirkun: 
zahlreicher hervorragender Fachgelehrten, yon A. Engler und 
Prantl. Royal, 8°. Leipzig: Wilhelm Engelmann. 
The first two fascicles of this important work are at hand. Each 
fascicle is to consist of 48 pp., and it is expected that about sixteen parts 
will appear yearly, which will complete the work in six or seven years. 
The first part is to embrace the Cryptogams, and is under the supervision 
of Dr. Prantl. The second to the fifth parts include the Phanerogams, 
edited by Dr. Engler. The list of collaborators is very large, and em- 
braces the most eminent German botanists 
seeds; geographical distribution; affinities; and classification. The 
latter includes an account of each tribe and genus, with remarks on 
principal species. The work is liberally and admirably illustrated. The 
ninety-six pages now published contain 564 single figures! The very low 
