BOOKS AND CURRENT LITERATURE 



185 



Among the orders which show the multiseriate ray is Sapindales. 

 Miss Holdeii" finds that Aesculus shows uniseriate rays normally, but 

 multiseriate rays in the petiole, root and reproductive axis, and infers 

 that this genus is a degenerate member of Sapindales, just as Castanea 

 and Cafstanopsis are degenerate members of the oak family. 



Miss Holden has also shown' that many species of Salix and Popuhis 

 have uniseriate rays, and parenchyma located at the outer edge of an 

 annual ring (terminal), but that primitive regions of the plants show 

 multiseriate rays and vasicentric parenchyma. It follows that the low 

 position in schemes of classification usually assigned to Salicales is not 

 borne out by anatomical data, but that the order appears to be a high 

 one showing features of reduction. 



The foregoing studies form an admirable illustration of a saying of 

 Jeffrey, to the effect that recapitulation, reversion and retention are the 

 three R's of biological science. — M. A. Chrysler. 



^ Holden, Ruth, Some features in the anatomy of the Sapindales. Bot. Gaz. 

 53: .50-.58, pis. 2-3, January 1912. 



' Holden, Ruth, Reduction and reversion in the North American Salicales. 

 Ann. Bot. 26; 16.5-17.3, pis. 20-21, January 1912. 



