1885.] Botany. 713 
fact that flowers brought into my laboratory where they were not 
visited by insects, although they were kept in water, did not 
spring open. Repeated trials under different conditions showed 
that at the instant the sensitive surface was touched, the basal 
third of the wings and keel became strongly curved, and that this 
brought so great a tension upon the stamen-tube and pistil that the 
latter could not be held longer by the petals, as a bow when bent 
too far snaps its string and frees itself. 
The purpose of this ingenious mechanism is obvious. When 
the stamens spring out with such violence they throw the pollen 
forcibly against the body of any insect hovering over the flower 
or resting upon its wings and keel.— Charles E. Bessey. 
BoranicaL News. — The March and April numbers of the 
Western Druggist contain an interesting paper on plant hairs by 
Professor E. S. Bastin of Chicago. It is illustrated by numerous 
wood-cuts. In a recent number of the Gardeners’ Chronicle 
Mr. W. G. Smith furnishes an illustration of Peronospora effusa. 
It is in his well-known style, a style against which we are moved 
to protest vigorously. Conventionalized plant figures may be 
permissible in art, but certainly they are not in botany. Re- 
cent numbers of Hora (Regensberg) contain a paper on the lich- 
ens of the French Jura mountains, by Dr. F. Arnold——The 
most interesting paper in the May ’¥ournal of Botany is one by 
Mr. Spencer Moore upon the Identity of Bacterium fetidum of 
Thin, with soil Cocci, in which it is shown that the bacteria 
which produce or accompany “the sweating of the feet” are 
identical with those producing chemical action in the soil. In 
the latter situation they reduce the sulphates to sulphites, and the 
phosphates to phosphites, and in both situations are instrumental 
in’ setting free ammonia. r. Vasey’s Descriptive Catalogue 
of the Grasses of the United States, just received, is a valuable 
contribution to the literature of our Gramineæ. The genera are 
described, and under each are arranged all the species which 
occur within the limits of the United States. A few synonyms 
are given, enough to enable one to use the catalogue in connec- 
tion with the older manuals. A summary at the end of the vol- 
ume gives the whole number of genera in the United States as 
120, and of species 675. Following the catalogue proper is a 
synopsis of the tribes of North American grasses based upon 
and Hooker’s arrangement in the Genera Plantarum. 
Two years ago the same author published a somewhat similar 
catalogue in which there were 114 genera and 589 species. We 
will repeat what we have said several times already, that work of 
this kind coming from the Department of Agriculture at Wash- 
ington tends to raise the value of the department in the eyes of 
the scientific men of the country. 
