Periodical Literature 147 



storms in localities where squirrels are entirely excluded and 

 then without or with less injury to the buds. 



Forstzoohgische Notizen. Centralblatt fiir das gesammte Forstwesea, 

 March, 1906, p. 122 125. 



The Botanical Gazette notes the results of 

 Photosyyithesis experimental work by Miss Matthall and 

 and F. F. Blackman on temperature as a 



Temperature limiting factor for photosynthesis. In 



these investigations, they endeavored to 

 interpet the quantitative variations of the process in terms of the 

 three limiting factors, viz.: (i) intensity of illumination, (2) 

 temperature of leaf , (3) pressure of CO^. "When Hght is the 

 limiting factor equal intensities produce equal photosynthesis 

 with leaves of most various structure and type. At low tempera- 

 tures leaves as different as helianthus and cherry laurel have 

 similar photosynthetic maxima, but at high temperatures these 

 diverge. Thus, at 29.5" C. the former can fix twice as much 

 COj as the latter, requiring twice as much energy to do it, of 

 course. The essential difference in the photosynthetic activity 

 in different leaves lies, then, in that they have different coef- 

 ficients of acceleration of this function with increasing temper- 

 ature. So in nature it appears that the low pressure of CO.^ 

 (entailing slow diffusion after solution at the surfaces of the 

 leaf cells) and the low temperatures are the serious impedi- 

 ments to food making." 



Notes for Students Botanical Gazette. March, 1906 pp. 215-216. 



Two interesting paleobotanic finds are reported from France, 

 namely, a cone which seems to belong to Seqtioia gigantea and thus 

 demonstrates, that both Sequoias were in existence in the 

 Jurassic period ; and two pine cones, one of the Strobus type, the 

 other resembling Pinus Laricio, showing that both types ex- 

 isted in the Juras.sic period. 



SOIL, w.\te;r and climvte. 



The summer of 1904 from middle of April 



Drouth to end of August was specially drouthy in 



and middle Germany. Oberforstrat Thaler re- 



Forest Growth, cords observations of the behavior of forest 



growth during this period under varying 



conditions, secured by circular. As regards species the conifers 



