94 



THE STRUCTURE OF ECONOMIC PLANTS 



holds that the growing points of the two axes are different, and 

 that no homology between foliar and floral organs exists. He 

 concludes that the theory of metamorphosis does not apply in any 

 way to the flower, and that it is an autonomous structure. For 

 this reason, he dissents from the idea that the floral organs are 

 sporophylls, and suggests that the stamens be termed "micro- 

 sporangiophores," and the carpels "spermatophores." 



The Inflorescence. — In addition to variations in the struc- 

 ture of individual flowers, the character of the inflorescence may 



Fig. 35. Types of inflorescences. A, raceme (diagrammatic); B, corymb (diagrammatic); 

 C, umbel (diagrammatic); D, spike of plantain, after Bailey; E, catkin of willow; F, head 

 of clover, after Smalian. (From Smith, et al.. Textbook of General Botany.') 



be distinctive. Flowers occur separately in a terminal or axillary 

 position; or, more commonly, form a flower cluster in which they 

 are more or less closely arranged with reference to one another. 

 The development of the inflorescence may be mono^odial or sym- 

 podial. In the monopodial development, the inflorescences are 

 indefinite, and result from the formation of a series of branches 

 which arise from the main axis in acropetal succession. Where 

 the lateral branches do not rebranch, the inflorescence may be a 

 spike or raceme if the main axis is elongated; or a head or simple 

 umbel if it is unelongated. (Fig. 35.) In the spike, the flowers are 



