XIX 



THE CLASSIFICATION OF PLANTS 



261 



Apple and Pear (Pyrtis) 



Pistil. The pistil consists of five carpels which are united to one 

 another along their sides. In the Apple the five styles are united at 

 their base, but in the Pear they are free. 



FIG. 252. A, Twig of Apple ; B, longitudinal section of flower ; C, flower, with 

 corolla absent ; D, view of flower from below ; E, a single stamen ; F, pistil, 

 with portion of calyx. (One-fourth nat. size.) Ca, calyx ; p, petal ; st, stamens ; 

 s, style ; o, ovary. 



Fruit. After pollination the calyx tube which surrounds the pistil 

 swells up and produces an inferior fruit known as a pome. 



Hawthorn (Cratcegus] 



Pistil. The pistil differs from that of the Apple in consisting of only 

 two carpels and in being two-celled. 



Fruit. The portion of the receptacle surrounding the carpels 

 becomes hard and forms a stony endocarp. Thus, the fruit is a stone- 

 fruit with two stones. 



Ladies' Mantle (Alcheinilla)1\& stamens are definite, and the 

 anthers are one-celled. 



