394 BOTANICAL GAZETTE [NOVEMBER 
formerly thought to be absorbed or taken into the plant through the leaves. 
t is now thought that even the air must furnish its food to plants 
—— the roots.” —H. HASSELBRING. 
Biology of plants. 
ONE OF THE first to appreciate the modern ecological view-point was 
Professor Wiesner, who issued his classical Biologie der Pflanzen in 1889. 
A second edition of this work has appeared‘ in which no radical change of 
treatment is to be seen. Throughout the new edition, however, the contribu- 
tions of the past decade are found intercalated in their proper places. In 
the introduction there is a fuller setting forth of vitalism and mechanism. 
Among the topics which are added or much changed are polarity, light and 
rain adaptations, photometry (the author’s own work). The chapter on evolu- 
tion is also much changed, and the last part is largely new. The order of 
the chapters is as follows: SECTION I, Biology of the vegetative processes: 
the individual; survey of the plant forms according to their mode of life 
(biological types); primordia, development, form and direction of organs; 
polarity, correlations, and leaf position; complications in determining the 
causes of organic forms; rhythm of the vegetative processes; germination of 
seeds and buds; vegetative growth ; flowering and fruiting; rest periods and 
leaf-fall; adaptation of plants to external vegetative conditions; adaptation of 
plants to other organisms; specific adaptations, reproduction; life duration; 
vitality. SrcTION I{, Biological relations of reproduction; distribution of 
sexual organs; wind-pollinated plants; insect pollinated plants; other aids 
to pollination, and transitions from one form to another; reciprocal. pollina- 
tion; adaptations for self-pollination; protective adaptagens of flowers; 
apogamy. SECTION III, Distribution of plants; fundamental principles and 
problems; vegetation forms and formations; distribution areas of species, 
genera and families; principles of systematic phytogeography. SECTION IV, 
Development of the plant world (theory of descent). APPENDIX: Historical 
development of botany. Thus one may see how thorough and comprehensive 
is this cli treatise on plant biology, or, as we would say, ecology.— 
H. C. Cow 
Plant geography. 
THE SIXTH volume of the invaluable series, Vegetation der Erde, is by 
Drude himself and embraces much of the material which he has been gather- 
ing for years in his own home-land of Saxony.s Just as Graebner’s work on 
4 WIESNER, JULIUS, Biologie der Pflanzen, mit einem Anhang: die historische 
Entwicklung der Botanik. Zweite, vermehrte und verbesserte Auflage. 8vo. PpP- 
vill + 340. figs. 78 and z map. Vienna: Alfred Hélder 02. 
5 DrupkE, O., Der Hercynische Florenbezirk. 8vo. pp. xix + 671. pls. 5. figs. 16 
7 map. Leipzig; Wilhelm Engelmann. 1902. M30, bound A/31.50; to subscribers 
M20-21.50. 
