52 



STRUCTURAL BOTANY. 



posing the seed, immediately after flowering. The membranous 

 pericarp of Cohosh (Leontice) falls away early, leaving the seed 

 to ripen naked. In Yew (Taxus) the seed is never enclosed 

 wholly by its fleshy pericarp ; but in most of the other Coni- 

 fers, the close-pressed, carpellary scales cover the seeds. One- 

 seeded fruits, like those of Butter-cups, etc., are liable to be 

 mistaken for naked seeds. 



169 ^jggp 171 



Capsule, 167, of Scrophularia, 2-cclled; 168, of Datura Stramonium: 169, of Iris; 170, showing its mode 

 of dehiscence (loculicidal). 171, of Colchicuui, 3-celled. 172, Regma, ripe fruit of Geranium, the carpels 

 (cocci) separating from the axis and bending upward on the elastic styles. 



148. Dehiscence. The fleshy pericarp is always indehiscent. 

 Its- seeds are liberated only by its decay, or bursting in germi- 

 nation. So also in many cases the dry pericarp, as the acorn. 

 But more commonly the dry fruit, when arrived at maturity, 

 opens in some way, discharging its seeds. Such fruits are de- 

 hiscent. Dehiscence is either valvular, porous, or circumscissile ; 

 valvular, when the pericarp opens vertically along the sutures, 

 forming regular parts called valves. These valves may separate 

 quite to the base, or only at the top, forming teeth, as in Chick- 

 weed. We notice four modes of valvular dehiscence, viz. : 



1, Suthral, when it takes place at the sutures of any 1-celled 

 pericarp, as Columbine, Pea, Violet. 



2, Septicidal (septum, partition, ccedo, to cut), when it takes 

 place through the dissepiments (which are double, 132). The 

 carpels thus separated may open severally by sutures (Mallows), 

 or remain indehiscent, as in Vervain. 



3, Loculicidal (loculus, a cell, ccedo, to cut), when each carpel 



