44° BOTANICAL GAZETTE [ DECEMBER 
A REVISION of the North American Lemnacez has been published by 
Mr. Charles Henry Thompson.‘ It seems that this is the first revision of the 
North American species, and is based upon a study of the rich Engelmann 
collection, with Dr. Engelmann’s notes and sketches, together with material 
rom the most important collections of the country. The study of herbarium 
material was supplemented by an examination of abundant living material of 
phases result in different looking plants, andthe “resting phase,” when it 
occurs, is different from both. Naturally these various phases have brought 
confusion into descriptions. Spirodela is represented by its single well 
known species, Lemna contains six, Wolffiella three, and Wolffia three, one 
of which is new. The contribution is a very valuable bringing together of 
material.— J. M. C 
A BRIEF ACCOUNT of the life and work of the late Fredrick Wilhelm 
Klatt is given in the Bulletin [ Herbier Boissiers by Dr. Hans Schinz. He 
was born in Hamburg, February 13, 1825, and died March 3, 1897. He was 
best known to American botanists by his studies of the Compositae of the 
American tropics. The bibliography prepared by Dr. Schinz contains forty- 
nine titles, extending from 1856 to 1896.— J. 
THE SERIES of papers upon “ North American Coniferae,”’ published by 
Dr. Edson S. Bastin and Mr. Henry Trimble in the American Journal of 
* Pharmacy, from January 1896 to eg 1897, have been brought together in a 
convenient pamphlet form.— J. M. C. 
PARTS 155 to (58, and 161 to 163 of Die Natiirlichen Pflanzenfamilien are 
supplements to the second, third, and fourth volumes. Much interesting new 
material is brought together, and many of the families are brought up to cur- 
rent knowledge. It is interesting to note that the recent discovery of spermato- 
zoids in Cycas and Ginkgo (their discovery in Zamia being too recent to be 
included) has led to a modification of he characters asigned to gymnosperms, 
and has induced Dr. Englert Ginkgo from the conifers and 
make it the type of a distinct facaily , the Ginkgeacese, to which five or six fossil 
genera also belong. It is strange that this has not been done long ago, even 
before the spermatozoid discovery. The gymnosperms are further recast by 
recognizing six great groups (“classes” of Engler) instead of the usual four. 
We have been accustomed to cycads, cordaites, conifers, and gnetums; but 
the Engler classes now are Cycadales, Bennettitales, Cordiatales, Ginkgoales, 
Coniferae, and Gnetales. The numerous further changes in the grouping of 
‘Separate from the ninth annual Report of the Missouri Botanical Garden, pP- 
22, pl. g. tN. 1897. 
55: oe 1897. 
