264 BOTANICAL GAZETTE [September 



tion has been given thus far to the invisible chemical composition of v zygotes 

 in the generations following a cross. Pearl and Bartlett 19 have investi- 

 gated a cross between a yellow dent starchy maize and a white sweet maize, 

 and reach the conclusion that low fat content, low protein content, low ash 

 content, and perhaps also low crude fiber and low percentage of pentosans, 

 are inherited as Mendelian unit-characters independent of the units which 

 determine the externally distinguishable characters of color and starchiness. 

 As the method of arriving at this conclusion was indirect, it was impossible 

 to determine whether these chemical characters are also independent of each 

 other. The low grades of all these characters are dominant over high grades. 

 The authors assume that the absence of the genes for starchiness (ss) acts as 

 an inhibitor to these chemical units. It would harmonize better with the 

 presence-and-absence hypothesis to regard the low grades of the various 

 chemical substances here considered as the product of the interaction of the 

 corresponding genes with the gene for starchiness. The authors point out 

 that the result of this investigation should lead to a revision of the usual 

 interpretation of the oft-cited selection experiments of the Illinois Agricul- 

 tural Experiment Station. — Geo. H. Shull. 



Transition from root to stem. — Compton 20 has published a very 

 useful analysis of the theories of the anatomical transition from root to stem. 

 Its text is the recent notable publication by Chauveaud which Compton 

 regards as marking "an important advance in the study of seedling anatomy. 

 In these days, when many botanists are trying to orient themselves in the 

 very rapidly developing field of vascular anatomy, such comparative state- 

 ments are very helpful. — J, M. C. 



Embryogeny of Ranunculaceae. — Soueges has undertaken the 



mbry 



with 



« The 



four most recent papers in the series 22 continue the consideration of the 



Myosurus 



It is 



interesting to have the embryogeny of this form so thoroughly worked out and 



so well illustrated. — J. M 



** Pearl, R., and Bartlett, J. M., The Mendelian inheritance of certain chemical 

 characters in maize. Zeitschr. Ind. Abst. Vererb. 6: 1-28. fig. 1. 191 1. 



30 Compton, R. H., Theories of the anatomical transition from root to stem. 

 New Phytol. 11:13-25. fig. 1. 191 2. 



21 Bot. Gaz. 51:480. 191 1. 



23 Soueges, E., Recherches sur PembryogSnie des Renonculacees. Bull. Soc. 

 Bot. France 58:542-549, 629-636. 1911; 59:23-31, 51-56. 1912. 



