298 



ORGANOGRAPHY. 



Iris, {fig. 696), and Hibiscus {fig. 658). As in septicidal dehis- 

 cence, the valves may either carry the placentas and seeds with 

 them {fig. 667), as in the Hibiscus and Iris ; or they may break 

 away from the placentas, and leave them united in the form of a 

 central column {fig. 660) ; or each ovary may simply open at its 

 dorsal suture, and the valves bearing the dissepiments may re- 

 main attached to the placentas. 



In some forms of septicidal dehiscence the ovaries or carpels 

 separate without opening, as in the Digitalis, in which case they 

 may afterwards open by their dorsal sutures, or in a loculicidal 

 manner. In other cases, the axis is prolonged in the form of a 

 columella or carpophore, as in the Mallow and Castor-oil Plant 

 {fig. 661, a), and in the Greraniacese {fig. 662, a), Umbelliferge 

 {fig. 700), and the carpels which are united to it also sepa- 

 rate without their ovaries opening. The ovaries of such carpels 



Fig. 661. 



Fig. 662. 



J^. 661. Fruit of Castor-Oil Plant {Ricimis 

 cojjiwums), dehiscing inaseptiridal manner. 

 c,c,c. Carpels or ovaries, a. Columella, sd. 

 Dorsal suture where each ovary ultimately 



opens. Fig. 662. Fruit of a species of 



Geranium, e. Persistent calyx, a. Axis or carpophore from which 

 the ovaries, o, o, with their styles, t, t, are separating, s. Stigmas. 



frequently open afterwards by their dorsal sutures {fig. 661, sd). 

 When such carpels separate with a certain amount of elasticity 

 from the axis to which they are attached, as in some Euphorbi- 

 acese, they have been called cocci (fig. 661). By some botanists, 

 all carpels which thus separate from the axis in a septicidal 

 manner are termed cocci, and the fruit is described as clicoccous, 

 tricoccous, &c., according to their number. In some fruits, such 

 as those of the Linum catharticum, the ovaries open first 

 by their dorsal suture, and then separate from each other in a 

 septicidal manner. 



C. Septifragal Dehiscence. — In this form of dehiscence the 

 ovaries or carpels open by their dorsal sutures, and at the same 

 time the dissepiments separate from the walls and remain united 



