422 BOTANICAL GAZETTE [MAY 
carbon source, the male uniformly gave the higher yield. In all dextrose 
cultures where the yields were medium or high, the male showed much more 
sporangium production than the female, and the female was more vigorous in 
mycelial production. The male seems to have a somewhat higher maximum 
temperature than the female. The optimum for the female also seems to be 
somewhat lower.—WM. CROCKER 
Amylase of Rhizopus.——HarTer™ has made a study of the amylase of 
Rhizopus tritici, particularly the effect of various factors on its secretion and 
action. The best growth of the fungus, and also secretion of amylase, as 
indicated by the amount of hydrolysis of starch, was obtained with CZzAPECK’S 
nutrient solution, when ammonium nitrate was the source of the nitrogen; and 
starch the source of the carbon. Poorer results were obtained when sodium 
nitrate was used as the source of the nitrogen, and either cane sugar or glucose 
as the carbon source. Sweet potato bouillon, however, which contained both 
glucose and starch, gave the best results of all. The nutrient solution best for 
the growth of the fungus was also best for the secretion of the enzyme. The 
best temperature for the action of the enzyme was 45° C., and its action was 
practically nil at 60°. The secretion of the enzyme, as measured by the 
hydrolytic power of a unit weight of the enzyme powder, was much less when 
the fungus was grown at 40° C., the maximum temperature forits growth, than 
when it was grown at 9° C., which represents about the minimum temperature 
for its growth. While inet of the experiments, the data from which are 
recorded in this paper, have been tried out by other workers, using other 
species of fungi, this seems to be the first time that Rhizopus tritici has been 
used for such an investigation.—S. V. Eaton. 
Plants of Mississippi.—The greater part of a useful little volume by LowE” 
is occupied by an annotated list of the vascular plants of Mississippi, compiled 
from the ALLISON and Tracey herbaria and from the field work and collections 
of the author and his assistant, Taomas L. Bamey. A feature of the work 
which should appeal to the general reader is an introduction comprising an 
technical language. Botanists will be more interested in the division of the 
state into the ten following topographic and floristic regions: (1) Tennessee 
River hills, (2) Northwestern prairie belt, (3) Pontotoc ridges, (4) Flatwoods, 
(s) North central plateau, (6) Jackson prairie belt, (7) Loess or bluff hills, (8) 
Yazoo-Mississippi delta, (9) Long leaf pine belt, (10) Coastal pine meadows. 
The topography, soil, and vegetation of each of these subdivisions are briefly 
described and lists of characteristic species given. The usefulness of the volume 
would be decidedly increased by supplementing the table of contents with an 
adequate index.—Geo. D. FuLtEr. 
6 Harter, L. L., Amylase of oe ee tritici, with a consideration of its secretion 
and action. Tie Agric. Res. 20: 761- 1921 
17 Lowe, E. N., Plants of aie Miss, Geol. Surv. Bull. 17. pp. 292. 1921+ 
