486 BOTANICAL GAZETTE [june 



cm 



stretch from surface to surface without intercellular spaces. Consequently the 

 width of the lines of starch produced at the edge of the darkened region is not 

 widened even though the unlighted area is supplied with C0 2 under abnormal 

 pressure. If the net be coarse the zone of marginal starch will be wider than if 

 it is fine. Diffusion of self-produced C0 2 to 2-5 cm at most is thus possible; for 

 in parallel-veined leaves of Triticum, Hordeum, and Zea, though the veins do 

 not prevent diffusion, the intercellular passages are so narrow as to limit it to 3 

 In Tradescantia and Acorus the transverse anastomoses prevent more extensive 

 movement. In Eichhornia, Pontederia, and Eucomis the leaves have spacious 

 intercellular passages, and so the movement is much more free. But even here 

 the diffusion scarcely surpasses 3 cm , unless through a region of the leaf that is not 

 in condition to act on the C0 2 . In nature, therefore, movement of C0 2 may be 

 considered practically nil. — C. R. B. 



Seedling of a graft-hybrid. — Certain branches of the graft hybrid, Cytisus 

 Adami, revert, producing flowers having the characters of the reputed parents 

 C. Ijxburnum and C. purpureas respectively. The C. Adami flowers are ordinarily 

 sterile, while those borne on reverted branches reproduce their respective parents. 



In May, 1904, Hildebrand^s observed that several flowers of a C. Adami 

 branch of a cultivated specimen in the Freiburg botanical garden had set seed, 

 and was able to obtain three fruits from them, which had chiefly the characters of 

 C. Laburnum, but in certain respects resembled C. purpureas. It is not known 

 whether these flowers were self-pollinated, but it is not unlikely that the pollen 

 came from C. Laburnum flowers, since the C. Adami flowers are usually sterile. 

 Two of the seeds germinated. Both were very similar in character to C. 

 Laburnum and in 1907 one of them produced hundreds of flowers, all having the 

 characters of C. Laburnum. No conclusions can be drawn regarding the heredi- 

 tary bearing of these facts, in the absence of a knowledge of the manner of pollina- 

 tion of the flowers and the nature of the next generation of offspring.— R. R. 

 Gates. 





Chlorophyll. — The discussion as to the phosphorus content of chlorophyll 

 waxes warm. Stoklasa replies vigorously* 6 to Tswett's criticisms^ and takes 

 issue with Willstatter's results.** The question is yet in the stage of polemic 



35 Hildebraxd, Friedrich, Ueber Samlinge von Cytisus Adami. Ber. Deutsch. 

 Bot. Gesells. 26a: 590-595. 1908. 



36 Stoklasa, J., Bralik, V., und Ernst, A., Zur Frage des Phosphorgehaltes 

 des Chlorophylls. Ber. Deutsch. Bot. Gesells. 27:10-20. 1909. 



37 Tswett, M., 1st der Phosphor an dem Anbau des Chlorophylline beteiligt ? 

 Ibid. 26a 1214-220. 1908. 



3* Willstatter, R., Zur Kenntniss der Zusammensetzung des Chlorophylls. 



Liebig's Annalen der Chemie 350:48-82. 1906. 



UND 



267-287. 1907. 



Ibid. 358: 



