DEVELOPMENT OF PLANTS 



365 



in these sporangia as already noted in the gymnosperms and 

 usually but one megaspore is developed in each sporangium (Fig. . 

 261B, 2). 



124. Development of the Flower of Angiosperms. — The sporo- 

 phylls are variously associated in groups that are commonly 

 called flowers. In its simplest form, the flower may be defined 

 as a minute branch or receptacle bearing one or more sporo- 

 phylls. Such a type is illustrated in the cat-tail (Fig. 262, B, C) 



m 



Fig. 262. Forms of primitive flowers: A, inflorescence of Typha or cat- 

 tail — mi, region bearing only flowers with microsporophylls; mg, flowers with 

 megasporophylls; b, bract. B, flower consisting of two microsporophylls 

 which are sessile on a short stalk that has numerous hairs. C, flower consis- 

 ting of one megasporophyll^5, stigma; 0, ovary surrounded with hairs. D, 

 early appearance of the inflorescence of Salix or willow. E, inflorescence 

 bearing only megasporophylls. F, flower, of a single megasporophyll with 

 forked stigma — b, bract; n, nectar gland. C, inflorescence bearing only 

 microsporophylls. H, flower of two microsporophylls. 



where the flower consists of one or a few sporophylls associated 

 with hairs, and also in the willow where the sporophylls are 

 developed in the axil of a minute bract (Fig. 262, F, H). It 



