HERBACEOUS AND WOODY DICOTYLEDONS 407 



PRUNUS (CHERRY) 



Reproduction. The flowers of the cherry are borne in lateral 

 buds on dwarfed shoots called spur shoots. The flowers are perig- 

 ynous (Fig. 257, /, and 259, &), as in the genus Rosa, but there 

 is only one ovary in the urn-shaped receptacle of each flower. 



FIG. 257. Black cherry (Prunus serotina) 



a, winter twig; 6, portion of the same enlarged; c, d, a leaf and the leaf margin; 



e, racemose inflorescence ; /, perigynous flower in section ; g, fruit cluster. From 



"Michigan Trees." Photograph furnished by Dr. Charles H. Otis 



In the ripening of the fruit the pistil forms the entire fruit, the 

 inner portion of the ovary wall forming the stone and the outer 

 portion the fleshy part of the fruit. The receptacle and the 

 floral parts formed upon its upper margin disappear with the 

 development of the fruit (Fig. 257, g, and 259, c). 



