THE AMERICAN NATURALIST. [Vol. XXXVII I. 



the similarity is at once apparent. In some plants, probably but 

 a year old, there were found many cases where the first leaf of 

 sprin<( (growth was simple and emarginate, but like that of the 

 first nepionic, much broader than the later 

 leaves (Fig. 15). The stipules were also 

 larger than in succeeding stages and in this 

 again comparable to the first nepionic leaf of 

 the seedling, showing a more accelerated con- 

 dition. In all cases the second leaf of spring 

 growth was trifoliolate. Those which were 

 found with the spring growth starting off 

 with a simple leaf were obtained in a situa- 

 tion unfavorable to the plant and thus favor- 

 ing such retarded conditions of growth. The 

 overlying loam had been removed from a 

 glacial sand i)lain, leaving the sand exposed 

 -11 south sloi)c. This gave a poor supply of 

 ;iM,.turc and exposed the plants to the full 

 toRc of the sun. As a result, the plants 

 showed a retarded development. 



In the adult plants, when in flower, cases 

 of localized senescence are not infrequent. Below the flowers, 

 the last leaf is often simple, comparable to the first nepionic 

 Irat of the seedhng ( iMg. 14). and to the first leaf of spring 

 growth in teeble or retarded phuits (iMg. 15). This reversion- 

 ary coiuhtion below the Hower is not usually shown, however. 



Rituux aci tosclla \.. Figures 17-19- 

 ( Sheep Sorrel.) 



The peruhar anricled tonn of the leaves of this plant fur- 

 nishes a means tor study of stages, altliough the leaf is not 

 compound as in the preceding cases. The seedhng ( I'ig. IJ) 



