﻿64 BOTANICAL GAZETTE [january 



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Noll's fine work on Cucurbita/'^ which in essentials antedates about all that 

 might otherwise be novel or valuable in this paper from the Leipzig labora- 

 tory. — E. B. COPELAND. 



Hartley, '7 in studying the effects of premature pollination in tobacco, 

 cotton, and tomato, has reached the following definite conclusions : ** that 

 the application of good tobacco pollen to immature tobacco pistils causes 

 the flowers so treated to fall from the plant because of the growth of 

 pollen tubes into their ovaries; that tobacco and tomato plants sometimes 

 set and ripen fruits without the flowers having received any pollen, and 

 that such fruits contain no germinative seeds ; and that but few fruits will 

 be .obtained by the pollination of immature cotton and tomato pistils, 

 but that good percentages may be obtained if the pollination is performed 

 when the pistils are receptive." — J. M. C. 



In a short paper on the controlling factors in the direction of branch 

 growth, Wiesner^^ suggests that the position of lateral branches maybe a * 



resultant due to the action of negative geotropism on the one hand and to 

 epinasty on the other. As the intensity of epinasty varies with age in some 

 forms, changes in direction which occur as a branch matures may often be 

 explained on this ground, the intensity of negative geotropism being constant 

 as long as growth continues. Since practically nothing is known as to the \ 



true nature of epinasty, and since quantitative measurement of geotropic 

 reaction is at least very difficult, it seems to us that such conclusions as the 

 above can be of little avail in advancing true physiology. — Burton E. Liv- 

 ingston. 



Weiss '9 has elucidated in an interesting way the structure of the 

 tracheary branches first described by Renault as occurring in stigmarian 

 rootlets.* He shows that these tracheary strands occur in typical monarchous 

 rootlets. They run from the protoxylem group across the generally lacunar 

 middle cortex of the root and end in a special organ composed of large 

 tracheary elements in the outer cortex. On account of the absence of 

 dichotomy, he draws the conclusion that they cannot be strands belonging 

 to branch-rootlets, but rather represent special water-absorbing organs 

 rendered necessary on account of the usually almost complete separation 

 of the central cylinder of the stigmarian rootlet from the outer cortex. 



E. C. Jeffrey. 



'^NoLL, F., Zur Keimungsphysiologie der Cucurbitaceen. Landw. Jahrb. Ergan- 

 zungsband I. 1901. 



^7 Hartley, Charles P., injurious effects of premature pollination; Bull. 22. 



Bureau of Plant Industry, U. S. Department of Agriculture. Oct. 4. 1902. 



^2 WiESNER, J., Regulirung der Zweigrichtung durch " variable Epinastie." Ber. 

 Deutsch. Hot. Gesell. 20: 321-327. 1902. 



^9 Weiss, F.E., The vascular branches of stigmarian rootlets. Ann- Botany 16; 

 559-574- P^' 26. 1902. 



