1914] CURRENT LITERATURE 539 
dark green plants of Melandrium are XXZZYYNN. This was shown by 
crosses between two light green types, chlorina and pallida. The F; generation 
was the typical dark green, while the F, generation consisted of dark green and 
light green in the ratio 9:7. Among the light green individuals both chlorina 
and pallida plants could be recognized, but just what characters the plants 
with the formula XXZZyynn possessed was not determined. 
produced progeny aces like the mother, no matter what characters were 
possessed by the male parent. 
2. These plants are called chlorinomaculata, because they are dark green 
spotted with the “chlorina”’ type of green. The transmission of their char- 
acters is not yet entirely clear. The progeny of a female plant crossed with 
pollen from flowers of different colored branches gave the following results: 
from variegated branches came green, variegated, and chlorophyll-free plants; 
from green branches came only green plants; and from chlorina branches came 
only Bagi free plants. 
se plants were of the yellowish aurea type. They were crossed 
ae many pene forms, but the results are somewhat complex, and the author 
does not commit himself definitely on their analysis. He thinks that possibly 
this may be a case of infectious chlorosis. He says: ‘While chlorosis of 
Abutilon and other Malvaceae is transmitted neither through the male nor 
the female gametes, this aurea character is carried by a part of the gametes of 
both kinds.” It seems to the reviewer that if this phenomenon is indeed one 
of infectious chlorosis, the small number of aurea plants of the filial generations 
might easily be due to reinfection —E. M. East 
Statistical methods in phytogeography.—In his attempts to obtain more 
exact data regarding the distribution of the various elements of alpine flora, 
Jaccarp” has developed certain statistical methods that have not only revealed 
several interesting facts regarding the vegetation of the Alps, but promise to 
be equally serviceable in the investigation of other areas. Having m a 
census of the areas to be compared, in this instance similarly situated localities 
of approximately the same area in various parts of the Alps, he applies for the 
analysis of his results his coefficient of community (C.c.), that is, 
No. of species common to two districts 100 _ Cc 
Total no. of species in the two districts : 
For alpine meadows at an altitude of 1900 m., several interesting results 
were manifest, such as: (1) the fact that the value of C.c. does not depend upon 
floral richness, but upon the ecological characters of the areas studied; (2) the 
 JaccarD, Paut, The distribution of the flora in the alpine zone. New Phytol. 
11°37-59. 1912 ah 
