DEVELOPMENT OF PLANTS 



381 



in these sporangia as already noted in the gymnosperms and 

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

 2615,2). 



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) 



\ "•- D G H 



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 consist- 

 ing of one megasporophyll — s, 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. G, 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 

 should be noted in the cat-tail that numerous spirally arranged 



