1915] CURRENT LITERATURE 335 
In the recent European literature we find a very interesting article by 
Cu HRISTY,% in which the author describes a gall Ponsa Snags for the 
) 
author has failed to find the mites in the British forms. It appears to 4 some- 
what similar to our American Acarus aenigma Walsh.—MeEt T. Coo 
Anthocyan pigments in plants.—In an examination of the recent work upon 
the occurrence and chemical nature of the red, purple, and blue plant pig- 
ments known as anthocyans, and yellow pigments designated flavones or 
flavonols, EvEREST”” has summarized the present state of our knowledge in 
a very concise manner. He shows that it has been established that (1) the 
anthocyans always occur as glucosides, and that some seven of these pig- 
ments have now been isolated; (2) the same pigment may be capable of 
showing a blue, purple, or red color, according as it exists as alkali salt, free 
pigment, or oxonium salt of some acid; all anthocyans do not, however, form 
blue alkali salts; (3) the anthocyans may be obtained from flavonols by 
reduction followed by spontaneous dehydration; and (4) glucosides of flavonols 
can pass, by reduction, to glucoside anthocyans without intermediate hydrol- 
ysis.—Geo. D. FULLER. 
Morphology of Gnetum.—THompson® has published a preliminary note 
on the embryo sac conditions in Gnetum, several species of which he has investi- 
‘gated. There are no vegetative cells in the male gametophyte, which is the 
expected contrast with Ephedra. Only free nuclei occur in the em 
before the pollen tube enters, although cells are formed before fertilization 
takes place, and one or more eggs are definitely organized. Perhaps the most 
significant observation is that before fertilization the female gametophyte 
becomes divided into a large number of multinucleate compartments, all the 
nuclei in each compartment later uniting to form a fusion nucleus, the endo- 
sperm being formed by the division of the fusion nuclei in the lower compart- 
ments. This situation is certainly very suggestive of a historical relation to 
the polar fusion in the embryo sac of angiosperms.—J. M. C. 
igin of stipules—The much debated question of the origin of stipules 
has received fresh light from the anatomical studies of SryNnotr and 
% Curisty, MILLER, Witches brooms on British willows. Jour. Botany 53: 
97-102. IQI5. 
27 EVEREST, ARTHUR E., Recent chemical investigations of the anthocyan pig- 
ments and their bearing upon the production of these pigments in plants. Jour. 
Genetics 45:361-367. 191. 
% THompson, W. P., Preliminary note on the morphology of Gnetum. Amer. 
Jour. Bot. 2:161. 1915. 
