CURRENT LITERATURE 
BOOK REVIEWS 
Biologic types 
In a recently published work Professor WARMING" has offered a valuable 
contribution to the knowledge of biologic types as these occur among plants. 
The subject is treated with rare skill, and although not a new one, the characteri- 
zation of the types is carried out in such a way that many new points have been 
brought together and explained by the author in accordance with his own views, 
and embodying many of the most important results from his long experience. 
The existence of biologic types was recognized many years ago. ALBERTUS 
Macnvs and Porta knew of them, but only vaguely. When therefore the 
author discusses the history of these types, he begins with ALEXANDER HUMBOLDT 
as the founder of plant-geography and physiognomy, so excellently outlined in 
his Essai sur la geographie des plantes and Ideen zu einer Physiognomik der 
Gewiichse. It is interesting to follow the course of development of this science, 
so very greatly influenced by the Darwinian era. Since then we have witnessed 
the publication of an enormous literature dealing with biology, biologic types, 
and plant societies, all more or less combined under the modern term ecology: 
A biologic type, according to the author, is the form which the vegetative 
organs have acquired in conformity with the surroundings; the particular struc 
tures, external and internal, which we find in stems and leaves, also in the 
complete shoot, but not in the flowers and fruits, which to a certain extent ar 
independent of the surroundings. The vegetative organs owe their various modes 
of development and structure to climate and soil, as related to the associations 
known as hydrophytes, mesophytes, and xerophytes. As understood by WARMING 
the biologic types comprise two large groups, heterophytes and autophytes. The 
former of these include holosaprophytes and parasites. The autophytes ~~ 
divided into five classes: aquatic plants, lichenoid plants, muscoid plants, 
and autonomic land plants. The sixth class comprises five subclasses: hapax 
anthic plants, redivive herbs, rosette plants, creeping plants, and erect plants 
with long shoots persisting through many seasons. 
The following examples may illustrate these subclasses. Among the ee 
anthic plants are those which are annual, biennial, and perennial, and W ‘ck 
bloom only once. The redivive plants (Stands of the Germans) are those Ww" 
die down to the ground at the end of the season, but which are Pro 
* WaRMING, E., Om Planterigets Livsformer. Copenhagen: G. E- C- Gad. 19% 
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