Current Literature. loi 



conditions by the senior author, on the geology by Tohnan, and 

 on the soils by Livingston. The latter is a continuation of the 

 studies reported in Publication 50 (F. Q. VI, 4, P. 3 8), and it 

 shows again the striking correspondence between the per cent, 

 water content of the soil and the distribution of the species as 

 well as that of the associations. 



Thornber in Chapter 4 gives a list of the species found in the 

 groups of habitats described above. There are 442 species of 

 seed plants on the four square miles under discussion. It is 

 interesting to note that only 3% of these attain the stature of 

 trees, 53% being annual and 20% perennial herbs. In the most 

 xerophytic habitats, however, namely the hill and the mesa-like 

 slopes 30% of the plants are woody and 43% are short-lived 

 winter annual and summer annual species. 



The remaining three chapters are devoted to articles by 

 McDougal of The Origin of Desert Floras, which is very general, 

 to Review and Discussion and to A Summary of Results by the 

 senior author. The volume is illustrated by most excellent photo- 

 graphic reproductions. C. D. H. 



A Phyto geographic and Taxonomic Study of the Southern 

 California Trees and Shrubs. By LeRoy Abrams. Bulletin of 

 the New York Botanical Garden. Volume 6, No. 21. Pp. 300- 

 485. 



The area studied comprises one-fourth of California. Southern 

 California is separated into three well defined floral divisions, the 

 costal slope, the mountains and the deserts. The species of the 

 costal slope are principally of Californian origin ; the species 

 confined to the mountains are boreal or of boreal ancestry and 

 those of the deserts are endemic or have migrated from adjacent 

 desert regions. In discussing the distribution of the trees and 

 woody plants of the region, the author follows Merriam's classi- 

 fication of life zones. The Hudson and Canadian zones in 

 Southern California intergrade, and they are characterized by 

 Pinus iiexilis, P. Murray ana and Populus tremuloides. Most of 

 Southern California belongs to the Austral Region. To the 

 Transition Zone of this region belong some fifty species of trees 

 and shrubs of which Pinus ponderosa, P. ponderosa, Jeffreyi and 

 Pinus Lamhertiana are characteristic. Owing to the large 



