58 STRUCTURAL AND PHYSIOLOGICAL BOTANY. 



485. The axis of the fruit is often called the columella ; 

 the space where two carpels unite is named the commissure. 



486. All fruits which are mere modifications of a single 

 carpellary leaf (406) have always a suture corresponding with 

 the junction of the margins, or with the placenta?, and often 

 another corresponding with the midrib of the carpellary leaf : 

 the former is called the ventral, the latter the dorsal suture. 



487. If the pericarp neither splits nor opens when ripe, it 

 is said to be indehiscent , if it does split or open, it is said to 

 dehisce, or to be dehiscent ; and the pieces into which it splits 

 are called the valves. 



488. The dehiscence of the pericarp takes place in differ- 

 ent ways. 



489. If it takes place longitudinally, or vertically, so that 

 the line of dehiscence corresponds with the junction of the 

 carpels, the dissepiments are divided, the cells remain closed 

 at the back, and the dehiscence is called septicidal ; Ex. Rho- 

 dodendron 264 . 



490. Formerly, botanists said that in this kind of dehis- 

 cence the valves were alternate with the dissepiment ; or, that 

 the valves had their margins turned inwards. 



491. If it takes place vertically, so that the line of dehis- 

 cence corresponds- with the dorsal suture (486), the dissepi- 

 ments remain united, the cells are opened at their back, and 

 the dehiscence is called loculicidal ; Ex. Lilac, Lily. 



492. Formerly, it was said that in this kind of dehiscence 

 the dissepiments were opposite the valves. 



493. When a separation in the pericarp takes place across 

 the cells horizontally, the dehiscence is transverse ; Ex. Ana- 

 gallis. 



494. If the dehiscence is effected by partial openings of 

 the pericarp, it is said to take place by pores ; Ex. Poppy. 



495. Sometimes the cells remain closed, separating from 

 the axis formed by the extension of the peduncle (284) ; Ex. 

 Umbelliferae, Euphorbia 255 . 



496. Or the cells open and separate from the axis, which 

 is formed by a cohesion of the placentse which separate from 

 the dissepiments ; Ex. Rhododendron 264 . 



497. Sometimes the dissepiments cohere at the axis, and 

 separate from the valves (487) or back of the carpels; Ex. 

 Convolvulus. 



