348 



PRIMITIVE FLOWERS 



spores originate in these sporangia as already noted in the gymno- 

 sperms 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) 



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 microsporo- 

 phylls which are sessile on a short stalk that has numerous hairs. C, 

 flower consisting 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 mega- 

 sporophyll with forked stigma — b, bract; 11, 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). These 



