THE ESSENTIAL ORGANS THE PISTIL. 



135 



number of constituent carpels. Moreover these distinct stigmas are occa- 

 sionally split down into two arms (stigmata bicruria), corresponding to 

 the two placentas below : the one-celled ovary of Grasses and Composite 

 (fig. 264) bears a two-armed stigma ; and the* stigmas of the compound 

 ovaries of Euphorbia and some Droserce are double the number of the 

 carpels. Sometimes the distinct arms of different carpels cohere, and 

 form stigmas equal in number to the placentas, but alternating with them. 



Form and Position. Stigmas, simple or compound, when distinct, 

 are either terminal or lateral : in the latter case the stigmatic sur- 

 face is on the ventral side. Their form is generally slender and 

 thread-like, with a glandular stigmatic surface ; but in the Grasses 

 the stigmas are feathery (fig. 257) or penicillate (fig. 258) ; in the 



Fig. 263. 



Fig. 264. Fig. 265. 



Fig. 266. 



Fig. 267. 



Fig. 263. Flower of Luzula, with one style and filiform stigmas. 



" " -" T- " "" " illose surfaces. 



yules at the base. 



Fig. 267. Young female blossom of Juniperus, with the front carpel remoyed, showing the 

 naked ovules. 



Iridaceae they are petaloid (fig. 259) or very much enlarged, as in 

 Iris (fig. 260) ; and in other cases they are capitate (fig. 256), 

 loled (fig. 261), peltate, radiate (fig. 262), filiform (fig. 263), linear 

 (fig. 264), &c. In Leguminosae the stigmatic surface of the simple 

 style is lateral (fig. 265). 



The orifice of stigmas leading to the canal of the style is more or less 

 filled by the glandular and capillary processes which clothe their sur- 

 faces ; and, indeed, to the naked eye, the canal of the style does not 

 appear permeable. 



Gymnospermous Pistils. The pistil of Gymnospermous plants 

 consists of scales or open carpels, collected into cone-s, bearing exposed 



