1913] CURRENT LITERATURE 407 
may or may not be produced; spermogonia are produced, but perithecia and 
conidia have not been observed. 
Another important contribution to our knowledge of American cecidology 
comes from CosENS,'s of the University of Toronto. After a brief review of 
our present knowledge of cecidology, he discusses the results of his own investi- 
gations. The subdivisions are arranged with reference to the insects causing 
the galls, but the discussions are primarily botanical in character. The results 
of these studies confirm much of our previous knowledge and make valuable 
additions. The Eriophyes galls show a well defined series from simple indenta- 
tions to well developed pouches, and from modifications of epidermis only 
to the palisade and mesophyll also. The modifications are those of degree 
rather than of kind. In the hemipterous galls the stimulation is from one side 
and is disseminated equally in all directions. The lepidopterous galls are 
dnaalieed as a simple type. The glands are larger than in the normal 
tissues. The dipterous galls are extremely variable in degree of complexit 
and the glands are very abundant. The sawfly galls of the Hymenoptera 
show a great tion of tissue, with but very little differentiation. Tannin 
was especially abundant in the eptdereix and bast and probably serves for the 
1 
of changing starch to sugar, which acts on the starchy saber Sete of the 
nutritive zone and accelerates the rate of their change to sugar. The material 
thus prepared supplies nourishment for both the larva and the gall. The 
protoplasm of the latter is thus rendered unusually active, since it receives an 
abnormal quantity of available food material in a limited area. The hyper- 
trophy and cell proliferation and probably also the appearance of vestigial 
tissue or other primary characters are the response of the protoplasm of the 
host to the additional food supply.” The author also says that it is not neces- 
sary in all cases for the stimulus to be applied to the cambium, but that it 
may be applied to any actively growing tissue; that this stimulus acts on 
tissues at considerable distance from the point of SS that certain 
inquilines have the power of gall production to some exten 
A very brief paper on pistillody by Lewis shows a necessity for 
botanists to give more attention to the recording of the abnormal structures 
in plants. In this case both the anther and the filament were inflated and 
bore ovules, the anther being modified into a sessile leaflike structure with a 
stigmatose edge. 
*s CoseNns, A., A contribution to the morphology and biology of insect galls. 
Trans. Canadian Fast, 114:3297-387. pls. 13. 1912. 
% Lewis, I. W., Pistillody in Argemone platyceras Link and Otto. Torreya 
12:85-88. 1912. 
