248 
ORGANOGRAPHY. 
BOOK 1. 
The raphe is always a true indication of the face of the 
seed ; and it is very remarkable that the apparent exceptions 
to this rule only serve to confirm it. Thus, in some species 
of Euonymus in which the raphe appears to pass along the 
back, an examination of other species shows that the ovules 
of such species are in fact resupinate ; so that, with them, the 
line of vascularity representing the raphe is turned away from 
its true direction by peculiar circumstances. In reality, the 
chalaza is the place where the secundine and the primine are 
connected ; so that in orthotropous seeds, or such as have the 
apex of the nucleus at the apex of the seed, and in which, 
consequently, the union of the primine and secundine takes 
place at the hilum, there can be no apparent chalaza, and 
consequently no raphe : the two latter can only exist as dis- 
tinct parts in anatropous or amphitropous seeds, where *the 
base of the nucleus co-rresponds to the geometrical apex of 
the seed. Hence, also, there can never be a chalaza without 
a raphe, nor a raphe without a chalaza. 
Something has already been said 
about thean'Z {figs. 189. and 190.) 
when speaking of the ovule; but 
it more properly comes under con- 
sideration along with the ripe seed* 
As a general rule, it may be stated 
that every thing proceeding from 
the placenta, and not forming part 
of the seed, is referable to the aril. 
Even in plants like Hibbertia volu- 
bilis and Euonymus europaeus, in 
which it is of unusual dimensions, 
it is scarcely visible in the unimpregnated ovary ; and it is 
stated by Brown, that he is not acquainted with any case in 
which it covers the foramen of the testa before impregnation. 
The term aril has been misapplied in many cases to the testa, 
as in Orchidaceae ; and even to a pair of opposite confluent 
bracts, as in Carex: of these errors, the former arose from 
imperfect observation, the latter from ignorance of the funda- 
mental principles of Organography. 
The mass enclosed within the testa or outer integument is 
190 
