STRUCTURE OF THE FRUIT. oe 
each flower (p. 15). A 2-celled fruit having its seeds on 
parietal placents, and which is divided by a false dissepiment, 
or replum, is. called a siliqua or silicula (p. 18), and it 
opens by the whole valve on each side falling away from the 
placentee. Here the dehiscence is manifestly at the ventral 
sutures, the valves representing the whole of the carpellary 
leaves except the extreme margins, which are persistent. It 
is manifest also from this that the replum of the siliqua is 
not the same morphologically as the dissepiment of any other 
2-celled ovary—viz., part of the blade of two cohering carpel- 
lary leaves—but is instead a production of the substance of the 
placentee. 
~All other forms of dehiscent fruits are termed capsules, but 
the manner of their dehiscence varies. The following are the 
_ chief modes :— 
1. By teeth, as in Chickweed (p. 24). Here there are 3 
_ earpels united into a 1-celled ovary with free-central placenta- 
tion, and the capsule dehisces by 6 teeth. It can be easily 
geen on examination that three of these teeth represent the 
dorsal sutures of the carpels, and 8 the lines of the suppressed 
dissepiments. Another excellent example is furnished by the 
Primrose, where a capsule made up of 5 carpels dehisces by 
{0 teeth. . 
2. By valves; and this valvular dehiscence usually follows 
one of three modes :— 
a. Loculicidal,* when the dehiscence takes place at the 
dorsal sutures of the carpels, and the walls fall out, carrying 
the dissepiments with them (p. 90). 
Fig. 90. Capsule of cb 
Hig. 89), Diagram ot Libertia, with lo- ae, 
foculicidal capsule. eulicidal —_dehis- PGs Ph ISG os 
cence, septifragal capsule. 
_ 6. Septifragal,t where the dehiscence takes place at the 
junction of the wall and the dissepiments, and the former 
falls out, leaving the latter standing. as in Rhododendron. 
c. Septicidal,} where the dehiscence takes place at the 
ventral sutures, so that the original carpels fall away from 
each other (p. 71). ; 
* Lat. loculus, a little place ; cedo, I cut. 
} Lat. septum, a division ; frango, I break. 
$ Lat. septum, and ceda. 
