254 j^nssoirs witm plants 



strawberry is one of the rose family. We have already seen (172, 

 173) that the hepatioa is held to be apetalous, and the strawberry 

 flower is reinforced (171 j. A most important gross difference between 

 the two, however, is the fact that the hepatiea is hypogynoug, 

 while the strawberry is essentially perigynous (170). 



295. In a short time (let the pupil determine 

 how long), a strawberry (Fig. 239) stands where the 

 flower was. There was no obvious promise of such 

 a structure in the flower. If we cut the straw- 

 berry across, we find no seeds in it, and it can- 

 not, therefore, be a pistil. The numerous pistils 

 which we saw in the flower are borne upon the 

 outside of the strawberry, and are akenes. The 

 edible part, therefore, must be a receptacle. 



296. The pupil sees that the straw- 

 berry in Fig. 239 is symmetrically 

 developed, both as to form and as 

 to number and arrangement of akenes. 

 Fig. 240. j^jg_ 240 is a malformed or "nubbin" 

 ^'"''"'l^ll^Z'^^ strawberry. If the pupil were to 

 examine such berries, he would find 

 that a deformity in any portion of the edible re- 

 ceptacle is generally associated with non- develop- 

 ment of the akenes. 



Suggestions. — Now determine whether failure of the akenes in 

 the strawberry is the cause of the malformation, or whether an 

 injury to the receptacle is the cause of both the malformation and 

 the failure of the akenes. Before fertilization takes place, cut the 

 styles from several of the pistils at one point, and see if the 



