DEHISCENCE. 



289 



the midrib. Legumes usually dehisce by both sutures (as in 

 Fig. 619), therefore into two valves. 



546. A dehiscent pericarp formed of two or more carpels is 

 called a CAPSULE. The two leading terms descriptive of capsular 

 dehiscence were based upon the modes of opening of pericarps 

 having as many cells as carpels : they are the septicidal, that is, 

 as the term denotes, cutting through the septa or dissepiments ; 

 and the loculicidal, that is, cutting into the loculi or cells. 



547. Septicidal, the dehiscence through the dissepiments, is 

 the disjunction of a pericarp into its constituent carpels, these 

 then usually themselves dehiscing down their ventral suture, 



as in Fig. 612, illustrated by 



the diagram, Fig. 613. Good 



examples are furnished by the 



Hypericum Family (the pistil 



illustrated in Fig. 536, 537), 



where the placentae which 



compose the axis are carried 



away on the edges of the par- 

 titions or introflexed valves ; 



also by Rhododendron, Kal- 



mia, and the like, in which 



the placentae remain combined 



into a column in the axis (the 



COLUMELLA or column) , from 



which the edges of the valves 



break away. 



548. The septicidal dis- 

 junction of the carpels does , 

 Onot of itself open the cells. 

 Such separated carpels when 

 613 one-seeded not rarely remain 



closed, as in Mallow, Ver- 

 bena, dec. Or when dehiscent they may open both by the ventral 

 and dorsal sutures; i. e., the pericarp may first divide into its 

 constituent carpels, and then each carpel break up into half 

 carpels, as in Euphorbia. 



549. Loculicidal, the dehiscence into the loculaments, loculi, 

 or cells of the pericarp (shown in Fig. 614, and the diagram, 

 615), is that in which each component carpel splits down its 



PIG. 612. Septicidally dehiscent tricarpellary capsule of Elodes Virginica. 613. Dia- 

 gram of septicidal dehiscence. 



FIG. 614. Loculicidally dehiscent tricarpellary capsule of an Iris, divided trans- 

 versely at the middle. 615. Diagram of loculicidal dehiscence. 



