33° 



ANGIOSPERMAE—DICOTYLEDONES 



/ 



there is a deep involution directed forwards and downwards, and fitting into a 

 corresponding pit in the upper surface of the adjacent carinal petal. The epidermal 

 cells are here so closely interlocked that it is scarcely possible to separate the carina 

 and alae without tearing them. There is also an anterior alar fold, which lies in 

 a carinal depression. The upper side of the base of the vexillum possesses two 

 deep but narrow indentations which project ventrally as firm ridges. These diverge 

 in front and fit into the anterior alar folds. The base of each carinal petal expands 

 into an upwardly and inwardly directed lobe, which rests on the sexual column. 



Fig. 107. Pisuni sativum, L. (after Herm. Miiller). (i) Flower after removal of the left ala, seen 

 from the left. (2) I^elt ala seen from within, •{y) Vexillum seen from within, (4) Carina seen from above 

 (further enlarged), (s) The same surrounded by the alae; anterior part omitted (still further enlarged). 

 (6) Basal part of the left ala, seen from the outside- (7) The sexual organs removed from the bud. (8 Upper 

 part of the style, seen from within (x 7). (9) A stamen, a, apical carinal swelling; b, median carinal 

 outgrowth; c\ alar involution, fitting .into carinal pit (c) ; d\ anterior alar fold, resting in carinal 

 depression {d), and overlaid by vexillary ridge id"\\ c, basal carinal lobe; e posterior alar process; 

 yi alar plate, held in place by rounded vexiUar swelling (yO: /. tip of carina; st, stigma; o, stylar 

 opening. 



It is kept in place b}' a posterior alar process, directed backwards and inwards. 

 These processes, in their turn, are grasped by narrow alar plates which project 

 horizontally from them, and are backwardly directed. A rounded swelling on the 

 very broad and firm vexillar base presses against each of these plates. 



The style runs up vertically from the end of the horizontal ovary; its end 

 is curved inwards to such an extent that the terminal stigma faces almost directly 

 downwards towards the base of the flower. The inner side of the style is beset 

 with long bristly hairs for almost half its length. The tip of the carina is also 

 directed towards the base of the flower, and dilates into a pair of swellings which 

 enclose the anthers in the bud. The conical space thus bounded possesses an 

 opening through which the style can protrude. 



