ii8 



Elementary Botany 



In size they vary from -^\-^ to xinnr °f ^'^ inch. Generally 

 the grains are yellow, in species of Mullein they are red, in 

 some Willow-herbs blue, black in the Tulip, and in other plants 

 green or of a whitish colour. 



■ When the pollen is ripe the anther lobes open to let it fall 

 out. They open or dehisce in various ways. 



1. Longitudinal dehiscence, as in the Pine (fig. 219) or 

 Tulip, when there is a slit running along the face of the anther 

 from top to bottom. This is the commonest form. 



2. Transverse dehiscence, generally met with in unilocular 

 anthers, as the Lady's-mantle. 



tP 



Fig. 219.— Stamen 

 of Finns sylves- 

 tris, with Ion|;i- 

 tudinal dehis- 

 cence. 



Fig. 220.— Stamen 

 of Barberry, the 

 anther opening 

 by recurved 



valves. 



Fig. 221. — Stamen 

 of Rhododen- 

 dron^ each an- 

 ther-loTDc opening 

 by^ pOfe. 



Fig. 222. — Stamen 

 of Bay (Laur7is 

 nobilis\ with 

 two glands at the 

 base of the fila- 

 ment, the anther 

 opening by re- 

 curved valves. 



3, Porous dehiscence^ openings being produced either at the 

 apex of the lobe, as in the Rhododendron (fig. 221) j or in the 

 side, as in the Heath (fig. 223). 



4. Valvular dehiscence^ when a portion of the anther lobe 

 hfts up like a trap-door, as in the Barberry (fig. 220) or Bay 

 (fig. 222). 



Gyncecium or Pistil. — Each of the carpels of which the 

 pistil is made up consists, when complete, of a swollen basal 

 portion, the ovary ; above this a stalk or style, which is capped 

 by the stigma. The ovary is a hollow box containing one or 

 more rounded bodies, the ovules. Generally the carpels of the 



