311 THE STRUCTURE OF ECONOMIC PLANTS 



of the staminal column; and, in addition, tliere is a horn-like 

 projection on each wing which fits into the evaginations of the 

 keel. The release of tension in connection with pollination is 

 known as "tripping." 



The pistil consists of a single carpel which develops a one-celled, 

 superior ovary, and a smooth, awl-shaped style. (Fig. 157, C.) 



Fig. 156. Habit of leaves and inflorescence of Grimm alfalfa. 



McFarland Co.) 



(Photograph by J. Horace 



In the ovary, ii to 18 ovules are formed, according to Martin (xo); 

 while Cooper (9) reports a smaller range of 10 to ii. From one to 

 six ovules begin to develop after fertilization, the others aborting; 

 and, in heavy seed-producing strains, there is an average of three 

 to four seeds per pod. 



The mature fruit is a brown, curved or coiled, slightly pubescent, 

 indehiscent pod which may have two or three spirals. (Fig. 160, 

 A.') The fruit coat consists of three distinct regions, (i) The 



