624 General Notes. [ October, 
face of plants, but he thinks that the ultra-violet rays have little effect. 
The well-known fact that green plants transpire more rapidly in the 
light is explained on the ground of their absorbing the light by means 
of their chlorophyll, and thereby increasing the tension of the aqueous 
vapor in the cavities of the plant, and thus favoring its escape. This 
was studied experimentally by comparison of transpiration of green and 
of etiolated plants in the light, by researches in the spectrum itself, and 
by interposing a chlorophyll-solution. The opening of stomata in the 
light plays only a subordinate part in the increase of transpiration caused 
by light. 
INFLUENCE OF TEMPERATURE ON THE GERMINATION OF PINE SEEDS. » 
— Dr. W. Velten states that heating the seeds can exercise upon: their 
germination an effect which is favorable or unfavorable according to their 
physiological condition ; and, further, that the time during which they 
are heated is an important element, since he finds that a lower tem- 
perature for a long time has the same influence as a higher tempera 
ture for a proportionally short period. 
BOTANY or CALIFORNIA, VoL. I. — This work gives a systematic ac- 
count of the Polypetalous and Gamopetalous Exogens of California, of 
the whole eastern slope of the Sierra Nevada and of the ranges adja- 
cent to it on the east, from Arizona to Northern Nevada, and of South- 
ern Oregon. The Polypetalous orders have been elaborated mainly by 
Professor Brewer and Mr. Sereno Watson ; the Gamopetalæ by Pro- 
fessor Gray. Of the high character of a systematic treatise by the au- 
thors just mentioned it is quite unnecessary to speak, but we may be per- 
mitted to call attention to a fewof the special merits of the present 
volume. There are two keys, one analytical, the other synoptical, by 
which the determination of the order of a plant and its place in the 
system is rendered very easy. In these days when there can be no : a 
tendency in some quarters to go back to a false indexical method, which 
secures by hook or by crook merely the name of a plant, somewhat after 
the fashion of a pick-lock, it is pleasant to observe so effective a protest 
in the form of a sound, scientific, and yet most helpful brace of keys- 
The selection of the type has been made with great skill. The catch- 
words of the printed page stand out boldly, so that the eye can hardly 
fail to detect the object of search. And, lastly, there is a good sprinkling 
of interesting notes of a popular character throughout the work, and much 
prominence has been given to an account of the geographical range of 
the plants. With Gray’s Manual, Watson’s Botany of the Fortieth 
Parallel, and this work (soon, we hope, to be completed), the study of the 
plants with which one meets in his journey across the continent is now 
an easy task. It should be said that we are indebted to 
Pea co te AE Se Smt A eee "et aw ae ae Oe ee 
