1898] CURRENT LITERATURE 211 
discussion of the systematic value of organs. A constancy in the direc- 
tion of stem twisting, whose importance in classification has been worked out 
by the author, proves invaluable as a group character, while the importance 
of characters derived from tuber, rootstock, etc., seem to have been much 
overestimated heretofore. Zes‘udinaria Salisb. has been reduced to a sub- 
genus of Dioscorea, this south African genus having been based upon its 
tessellated aerial rootstock. The same rootstock was found on the Mexican 
Dioscorea macrostachya. 
The following classification is made of the “ edible” tubers of the family : 
1, Root structure : character uniform. 
2. Stem structure: a. growth directed downward, subterranean; 4. 
growth directed laterally, subterranean ; c. growth directed upward, above 
ground. 
The striking external differences in a, 6, and ¢ are the outcome of varia- 
tion in the relative position of the most active cambium, and this activity 
*xpresses itself quite independently of genetic relationship. 
Grisebach and Kunth based their system for the family chiefly upon the 
character of the staminate flowers, having had but few pistillate plants to 
‘amine. The result was that staminate and pistillate plants belonging 
‘ogether were usually described as separate species, and vice versa. This 
arrangement has been very largely abandoned by Dr. Uline, whose exhaus- 
fe study of larger and later collections has enabled him to clear away 
Many of the difficulties. 
: An undescribed kind of hydathode has been found on the leaves of cer- 
CaN species, and is briefly described. 
The chapter “ Das System” is but a forecast of the unpublished sys- 
tematic part, while that on « Geographie ” is of unusual value on account of 
oo Petbective, and on account of the exceptionally thorough repre- 
Station afforded by the material studied.— J. M. C. 
of 4 oma by Dr. H. L. Russell of the Agricultural Experiment Station 
allieg ey of Wisconsin, entitled “A bacterial rot of cabbage and 
of the or} has recently come from the press.t In it is given an account 
of oo. mode of transmission, and geographical distribution 
tb disease which for a number of years has been doing great 
The mena and allied plants in various parts of the United States. 
Producing rita Physiological, and culture characters of the organism 
been assisti a been carefully worked out by Mr. H. A. Harding, who has 
ins ng Dr. Russell, : 
4 paper, ag disease upon which Dr. E, F. Smith last year published 
Farmer's Bulleti 'n this volume, p. 67, and upon which later he issued a 
No oe 68) of the U.S. Department of Agriculture. The two 
+ 65, February 1898. pp. 39. figs. 15. 
