285 
interest connected with the genus Zuphrasia. After an introduc- 
tion and detailed discussions of the nomenclature, morphology 
and physiology, and a conspectus of the species, the author de- 
scribes the species, giving much detail in regard to the time of 
flowering, geographic distribution and specimens examined, all 
followed by copious critical notes. Eighty-seven species and 
twenty-one hybrids are enumerated. 
The excellent series of plates is divided between the anatomy, 
morphology and photographs of all the species, many taken from 
original specimens. The maps serve to show the geographic dis- 
tribution of some of the species and larger groups of the genus. 
Dr. Wettstein has divided Luphrasia officinalis, as generally 
understood by American botanists, into £. Americana Wett., E. 
latifolia Pursh, and E. Oakesti Wett., thus giving us three American 
species in place of one. £. Americana is said to extend from the 
region of the St. Lawrence River and the Great Lakes through 
Labrador; £. /atifolia occurs on the coasts of Labrador and Green- 
land, and extends through sub-arctic and arctic Europe to Asia; 
while 4. Oakesz is known from a single collection from the White 
Mountains, New Hampshire (not California as indicated by the 
author). We hope that Dr. Wettstein’s: interpretation of the 
American representation of the genus is more trustworthy than 
his geography. ite & 
Lehrbuch der Okologischen Phanzengeographie. Eine Einfiihrung © 
in die Kenntniss der Pflanzenvereine. By Dr. Eugen Warming. : 
German edition by Dr. Emil Knoblauch. 8vo., pp. 412. Bertin, 
1896. ee ee 
It is, however, very probable that Drude’s and Grisebach’s works 
on plant geography and distribution gave the impulse for pro- 
ducing it. It also seems evident that the author was strongly 
influenced by the numerous comparatively recent investigations 
on symbiosis, which no doubt suggested many of his ideas in re- 
gard to plant societies. 
Warming introduces the subject with a consideration of the 
In the arrangement of the subject-matter this work is original. 
ecological factors concerned in plant distribution. These are : : 
divided into direct and indirect (Schoum). In the former are in 
