FORESTRY. 639 



blooming, fruit developmeut, new bniucli growth, foliage, etc. The dillereuces 

 observed are here presented and discussed. As summarized they show that thus 

 far for the two years of experiment the water supply did not influence the 

 time of starting of buds. The trees which received an excess of water showed 

 the greatest number of blossom clusters; greatest average size, greatest average 

 weight, and bigliest quality of fruit; greatest total amount of wood growth; 

 greatest number of branches; greatest average linear growth to the branch; 

 greatest average diameter of wood growth; longest internodal spaces; greatest 

 number of cases of multiple growths from single buds ; largest, most conspicuous, 

 and greatest number of lenticels; greatest size, weight, and vigor of leaves; 

 greatest number of leaves affected with the apparent " sunbura " ; longest grow- 

 ing season; largest, healthiest, and most vigorous buds; and readiest formation 

 of callus tissue. The moderately watered trees had the largest total number of 

 blossoms and greatest number of fruits. The scantily watered trees led the 

 others only in having the largest average number of tlowers to the cluster. " Of 

 the lots which received the excess of water, the one which received water less 

 frequently showed a superiority only in that it had the greater number of 

 fruits, greater average weight to the leaf, and gi-eater average diameter of 

 new growth. On the other hand, the lot watered more frequently slightly 

 exceeded the other in all other respects." 



Blackberry culture, G. M. Dakrow {U. 8. Dept. Agr., Farmers' Bui. 643 

 (1915), pp. 13, figs. 8). — A. practical treatise on blackberry culture, discussing 

 the location of the plantation, soils and their preparation, propagation, pollina- 

 tion, planting, intercrops, cultivation, fertilizers, systems of training, mulching, 

 harvesting, yields, winter protection, duration of plantation, insects and dis- 

 eases, regional adaptability of varieties, hybrids and novelties, and blackberry 

 by-products. In the introduction statistics are given showing the acreage 

 devoted to the cultivation of blackberries and dewberries in the United States 

 in 1909. 



Strawberry varieties in Oreg'on, V. R. Gardner {Oregon 8ta. Bien. Crop Pest 

 and Hort. Rpt. 101.3-1//, pp. .50-94, fiff- i)- — This comprises descriptive notes on 

 varieties of strawberries which have been tested at the station during the 

 period 190S to 1913, icclusive. The characters described are such as have to do 

 Avith the horticultural value of both plant and fruit. Reference is made to the 

 history of each variety as far as known. A bibliography of cited references is 

 appended. 



FORESTRY. 



The temperature of leaves of Pinus in winter, J. H. Ehlers (Amer. Jour. 

 Bat., 2 (1915), ^0. 1, pp. 32-70, figs. 4)- — Results are given of an investigation 

 conducted in the arboretum of the University of Michigan with the view of de- 

 termining the internal temperature of pine leaves in winter under as nearly 

 natural conditions as possible. The species Pinus laricio ausfriaca was selected 

 for the purpose, the leaves of this species being the largest in cross section of 

 the conifer leaves available in the locality. An attempt was also made to ob- 

 tain direct evidence of photosynthesis under winter conditions by examining for 

 starch content the leaves of the various conifers growing in the university 

 arboretum. 



The data here presented show that evergreen conifer leaves even under winter 

 conditions maintain through the absorption of radiant energj' temperatures from 

 2 to 10° C. higher than the surrounding air. The UKSximum obtained under bril- 

 liant illumination and with a light breeze blowing was 8.83°. Where the leaf 



90853°— No. 7—15 4 



