334 : BOTANICAL GAZETTE [APRIL 
pages of systematic descriptions in connection with the plankton work, includ- 
ing both plant and animal forms; plant morphology receives some attention, 
and bacteriological and plankton technique are more or less fully described. 
One is doubtful whether the physiological viewpoint even prevails. 
The book is an outgrowth of exercises that have been used in teachers’ 
courses for fourteen years, involving at least 25 repetitions. In spite of this, 
one is unable to judge whether it is more a laboratory pia: or a descriptive 
text. It seems poorly suited for either —WiILLIAM CROCKE. 
Diseases of tropical plants 
Cooks has published a timely volume which introduces us in a compact 
way to the diseases of the tropics. The study of plant pathology has been 
chiefly with the crop plants of the temperate regions, but with the growing 
interest in tropical plants, there must come a knowledge of the tropical dis- 
eases. This vast field has yet to be developed, but the scattered literature 
that does exist should be brought together, and this Cook has done in a very 
effective way. The spirit of the book is modern, for instead of being merely a 
_ list of the parasites inducing diseases, there is a chapter on the nature and 
symptoms of diseases, and another on the structure and functions of plants. 
The classification of the disease-producing fungi is restricted to a single chapter, 
and then a series of chapters takes up the study of the best known tropical 
diseases. o final — discuss prevention and control, fungicides and 
spraying ake. —j.M.C 
A weed flora 
PAMMELS has set the pace for a comprehensive book on the weed flora of 
a state. He makes the statement that a conservative estimate of the damage 
done to the crops of Iowa by weeds is $25,000,000 annually. If this is true, 
it is certainly high time the farmers should learn to recognize the dangerous 
weeds and eliminate them. The contents of the volume can be best indicat 
by the chapter titles. The first chapter is a descriptive manual (400 pP .), iD 
which every weed is ainetreted and its disteivution through the state indicated 
uponamap. Th i ws: the general character 
of seeds; the mi pic structure of some weed seeds; morphology of flowers 
and leaves; scattering of weeds; roots and rootstocks of weeds; number 
kind of weeds in different soils; injuriousness of weeds; weed 5 ee 
medicinal weeds; phenology of weeds; weeds and seed laws.—J- M.C 
‘Cook, M. T., The diseases of tropical plants. 8vo. pp. xi+317- fés- %: 
London; Macmillan. 1913. $2.75. 
5 PamMEL, L. H., The The weed flora of Iowa. Iowa Geological Survey- Bull. no. 4* 
pp. xili+-o12. figs. 570. 1913. 
