122 



Elementary Botany 



Very often the style is absent, in which case the stigma is said 

 to be sessile upon the ovary. 



The stigma is intended to receive the pollen grains, and 

 hence its presence is necessary in the perfect pistil. It varies 

 much in appearance. In some cases it is merely an opening 

 at the top of the style, upon which is secreted some glutinous 

 fluid. In other cases it is variously enlarged. It is capitate, 

 or forming a head, in the Primrose and Lily (fig. 224) ; petaloid 

 in the Iris (fig. 233) ; penicillate, with 

 a number of hair-like arms, in the Pelli- 

 tory of the Wall (fig. 234) ; peltate, or 

 shield-like, in the Poppy (fig. 235). 



Fig. 233. — Petaloid stigmas 

 of Iris. 



Fig. 234. — ^Pistil oi Parte- 

 taria, with penicillate 

 stigma. 



Fig. 235. — Peltate stigma 

 of Poppy, with hypo- 

 gynous stamen. 



The ovule, when in a young state, consists simply of a mass 

 of parenchymatous cells ; these soon become surrounded by 

 coats, the primine {ai, fig. 236) and the secundine {it, fig. 236). 

 These coats are not complete, leaving an opening, the micropyle 

 (fig. 236, m), leading into the interior of the ovule, which is 

 composed of the original cellular mass forming the uucleus {k), 

 amongst which is one cell, the embryo-sac {em), larger than the 

 rest. 



The ovule is generally attached to the placenta by a short 

 stalk, the funiculus (/), but at other times it is sessile upon the 

 ovary. The point by which the ovule is attached to the 

 funiculus (or placenta) is the hilum, whilst the point by which 

 the nucleus is attached to the integmnents is the chalaza {c). 



