GROWTH AND DEVELOPMENT OF THE INFLORESCENCE AND FLOWER 



515 



The characteristic disposition of zygomorphic flowers— /.e., lateral 

 and approximately horizontal— has long been associated with insect 

 visitation and the biological advantages of cross-pollination. (See 

 summary of literature in Goebel, 1900). As early as 1819 A. P. de 

 Candolle had noted that the position occupied by a flower has a great 



Figure 16. Flowers of Stellaria media (L.) Vill., with perianth removed, 

 illustrating various stages of reduction in the number of stamens. (Original 

 drawings, C. W. Wardlaw.) 



