292 ORGANOGRAPHY. 



" That the stigma is always double appears probable, from 

 those eases in which it is either completely developed, as in the 

 greater part of Gramineae, where the ovarium is simple; in the 

 compound ovarium in Urena; and from those in which the de- 

 velopment, thougti less complete, is still sufficiently obvious, as 

 in many Euphorbiacefe and in several Irideae. This degree of 

 development, however, is comparatively rare, confluence be- 

 tween the two stigmata of each carpel being the more usual 

 structure; and in the compound pistillum a greater degree of 

 confluence often takes place in the stigmata than in the placentae, 

 — a fact which in all such cases is obviously connected with 

 adaptation of surface to the more complete performance of 

 function." In many Rosacese, as in the Rose, &c., the stigma is 

 notched on the side corresponding to that from which the pla- 

 centa arises, which is another proof of its double nature. 



The stigmas of a syncarpous pistil are generally opposite to 

 the cells, and alternate with the dissepiments, but it sometimes 

 happens, as in the Poppy {fig. 428), that half the stigma of one 

 carpel unites with a similar half of the adjoining carpel, and 

 thus it becomes alternate with the cells, and opposite to the 

 dissepiments. 



The term stigma is only properly applied to that portion of 

 the style which is destitute of epidermis and which secretes the 

 stigmatic fluid; but it is often improperly given to more divi- 

 sions of the style. Thus in the Iris (fig. 629), the three 

 petaloid portions of the style are by some botanists termed 

 petaloid stigmas; whereas the stigma is properly confined to a 

 little transverse space near the apex of each division. In many 

 plants of the natui-al order Leguminosas, such as Lathyrus 

 (fig- 588), Vicia, &c., the hairy part towards the summit of the 

 style has been termed a stigma, but the latter is confined to 

 the apex of that organ. In Labiate Plants also, the style fre- 

 quently divides above into two branches (fig. 594), and these 

 have been called stigmas, but the latter, as in the instances just 

 alluded to, are confined to the apices of the divided portions of 

 the style. 



We have already seen that the stigma may be separated from 

 the ovary by the style, or the latter organ may be absent, in 

 which case it is said to be sessile, as in the Barberry (fig. 569), 

 Poppy (fig. 428), Vine (fig. 506), &c. In Orchids the stigma 

 is sessile on the gynostemium (figs. 534 and 552), and ap]icars 

 as a little cup-shaped viscid space just below the attachment of 

 the pollen masses. 



In a syncarpous pistil the stigmas may be cither united 

 together, us in the Primrose (fig. 567), or distinct, as in 

 Linum (fig. 632), and Campamda (fig. 492); in the hitter case, 

 instead of looking upon these separate ]»arts as so many distinct 

 stigmas, it is usual to describe them as if they were portions of 



