188 
ORGANOGRAPHY. 
BOOK I. 
magnitude of two feet in diameter ; and from the texture of a 
delicate membrane to the coarse fabric of wood itself, through 
various cartilaginous, coriaceous, bony, spongy, succulent, or 
fibrous gradations. 
The base of the pericarp is the part where it unites with 
the peduncle ; its apex is where the style was : hence the 
organic and apparent apices of the fruit are often very dif- 
ferent, especially in such as have the style growing from 
their sides, as in Rosacea? and Chrysobalaneae, Labiatae and 
Boragineae. 
When a fruit has arrived at maturity its pericarp either con- 
tinues perfectly closed, when it is indehiscent, as in the hazel- 
nut, or separates regularly round its axis, either wholly or 
partially, into several pieces : the separation is called dehis- 
cence, and such pieces valves ; and the axis from which the 
valves separate, in those cases where there is a distinct axis, is 
called the columella. 
When the dehiscence takes place through the dissepiments 
it is said to be septicidal ; when through the back of the cells 
it is called loculicidal ; if along the inner edge of a simple 
fruit it is called sutural ; if the dissepiments are separated 
from the valves the dehiscence is named septifragal. 
In septicidal dehiscence the dissepiments 
divide into two plates and form the sides of y 
each valve, as in Rhododendron, Menziesia, / \ 
&c. Formerly botanists said that in this sort l — ^ a 
of dehiscence the valves were alternate with 
the dissepiments, or that the valves had 
their margins turned inwards. This may 
be understood from Jig, 168., which represents the relative 
position of parts in a transverse section of a fruit with septi- 
cidal dehiscence ; v being the valves, d the dissepiments, and 
a the axis. 
In loculicidal dehiscence the dissepiments ^^^^—^ I69 
form the middle of each valve, as in the lilac, 
or in the diagram 169., where the letters 
have the same value as above. In this it 
was formerly said that the dissepiments were 
opposite the valves. 
