CURRENT LITERATURE 
NOLES FOR STUDENTS 
Ecological classification.—In a moderate discussion of the classification of 
vegetation, TANSLEY' has clarified some obscure points and made several good 
suggestions. He insists that it is absolutely necessary to consider the units of 
vegetation as they actually occur in nature, and not to attempt to classify 
vegetation either by life forms or habitats. The natural units of vegetation 
regarded as quasi-organisms. In this respect the author takes what appears 
to be a safe stand midway between such extreme views as those of CLEMENTS, 
who regards vegetational units as true organisms, and those of GLEASON, 
who refuses to consider a unit of vegetation as an organic entity. The plant 
association” is regarded as the primary and fundamental unit of vegetation. 
In this TANSLEY is in agreement with a majority of ecological investigators, 
although he lays great stress upon the limitation of the term to mature units 
in relatively stable equilibrium with their environment. —, plant 
term 
species, it is suggested that CLEMENT’s usage be followed by designating them 
respectively “consociations” and ‘‘consocies.” 
The continued use of “formation” is recommended. The formation must 
be determined empirically, and it consists of a set of plant communities related 
developmentally and culminating in one or more associations. It is regarded 
as possible to distinguish climatic and physiographic (edaphic) formations, 
although not so sharply as has been done by Nicuots, because of the frequent 
transition region between two climatic regions. It is recommended that 
plant associations be named by their pin species, and the formations, 
whenever it is possible to do so, from the form of the vegetation —Gero. D. 
FULLER. 
Anatomy of Equisetum.—Several recent papers help considerably to settle 
the controversy over the fundamental nature of the bundles and the stele in 
Equisetum. Meyer? presents a detailed review of the vascular anatomy of 
* TANSLEY, A. G., ee —- of vegetation and the concept of development. 
Jour. Ecol. ry ee 
Meyer, F. J., Das  eitungsystem von Equisetum arvense. Jahrb. Wiss. Bot. 
59: 263-286. ie 7. 
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