Books and Current LitERATURE. 47 



J. C. Blunier, in a recent issue of Science, presents a cleaily 

 drawn picture of the plant geography of the Chiricahua moun- 

 tains of southeastern Arizona, from which it appears that the 

 tree growth of these mountains is quite similai to that described 

 by Mearns for a number of ranges of the nearby international 

 boundary. 



The lower Sonoran zone, characterized by cacti and thorny 

 shrubs, touches the Chiricahua mountains only at their eastern 

 base and both ends. The upper Sonoran completely encircles 

 them in a broad belt of evergreen brush land with oaks as leading 

 species, extending well into the transition zone, and there ming- 

 ling with the outposts of the coniferous forest which envelopes 

 all the remainder of the range with a mantle of needle-leaf 

 evergreens. 



The influence of aspect on local distribution is strikingly 

 shown, especially where, as in the case of two contiguous slopes 

 near Paradise, one faces north and the other south. The north 

 slope in this case supports a dense shrubby growth of Ceanothus, 

 Cercocarpus, and various other plants, from which grasses are 

 practically absent; while the south slope is entirely destitute of 

 trees and shrubs, and is covered with grasses. 



In regard to the influence of soil, it is shown that each 

 division or group of plant societies is peculiar to a class of rocks 

 and residual soils of its own, and, further, that the so-called ten- 

 sion lines between these societies or groups of such are usually 

 marked with great definiteness, and bear no relation to aspect. 

 Cases occur in which, if two quadrats of one thousand square 

 feet each were laid off, each on a separate formation, but ad- 

 joining one another on one side and on the contact line, not a 

 single woody species would be common to both quadrats, al- 

 though several such might be found on either one. 



The paper, embodying in condensed form the results of long 

 continued and exact observation, is a definite contribution to 

 our too limited knowledge of the factors deteimining the local 

 distribution of plants in the arid Southwest. 



J. Y. Bergen, in the Botanical Gazette for October, 1909, 

 gives an account of transpiration experiments with young seed- 



