PERIODICAL LITERATURE. 



Botanical Journals R. T. Fisher 



Foreign Journals B. E. Fernow, R. Zon, F. Dunlap 



Propagandist Journals H. P. Baker 



Trade Journals F. Roth 



FOREST BOTANY AND ZOOLOGY. 



The celebrated plant physiologist, J. Sachs, 

 Cause maintained that flowering was dependent 



of upon the presence of certain materials, pro- 



Flowering duced at certain periods and acting as stim- 



uli. In the "Naturwissenschaftliche Wo- 

 chenschrift" (1905, p. 573) the primary cause is sought in certain 

 weather conditions which produce these materials and act upon them. 

 That light is an essential factor in forming flower materials can be 

 proved by placing plants in dark rooms, when no flower buds will 

 develop; similarly, shrubs shaded on one side and exposed to sun- 

 light on the other flower mainly on the latter side. Flower materials 

 may, however, be deposited as reserve materials in bulbs, which may 

 then develop flowers in the dark. Temperature also influences flow- 

 ering favorably, but in the tropics excessive humidity may counteract 

 the favorable temperature influence, so that trees from the temper- 

 ate zones fail to flower, and the flowering time of the indigenous 

 plants falls in the dry season. Again the practice of pruning roots 

 to induce flowering means a reduction of water supply or of the for- 

 rpation of water-conducting tissue ; on the other hand pruning shoots 

 and thereby increasing water supply reduces flowering. 



Prof. Loew, of Tokio, considers sugar the flower-forming ma- 

 terial, and light, temperature, increase and diminution of water 

 supply favor its formation, the latter concentrating the sugar in 

 the plant; hence the remarkable flower show of cherries and plums 

 in Japan, where the climate is the cause of the fall of fruit before 

 ripening, which induces the deposit of the unused sugar as starch 

 and fat in the bark and this concentration accounts for the pro- 

 fusion of flowers (152 flowers on 10 inches of shoot were counted). 



These considerations may give a cue to the prediction of seed 

 years even in forest trees. 



Die Ursachen der Bliitenbildung. Centralblatt fiir das gesammte 

 Forstwesen. June, 1906, p. 286. 



