CONTRIBUTIONS TO BOTANY. 
239 
one margin of the seed, while all the four edges of the two eoty- 
ledons face the contrary margin, the albumen and integuments 
partaking of the same complicature. A deep groove is thus 
formed, reaching to the axis, as in R. catharticus, which here is 
therefore lateral, instead of dorsal ; the raphe does not lie in the 
bottom of the deep groove, as in the latter species, but as it 
leaves the chalaza it runs along the mouth of the groove from 
top to bottom, as in R. Alaternus, and the middle integument, to 
which it is attached, here makes a deep plicature which nearly 
reaches the bottom of the groove; and throughout the whole 
length of this plicature it is separated on both sides, by a vacant 
interval, from the inner integument, thus forming a kind of 
loose, incomplete partition all down the groove. This inter- 
mediate tunic is membranaceous, and invests all other parts of 
the seed ; it is enclosed within an external, hard, polished, 
testaceous covering, similar in texture and appearance to that in 
R. catharticus, but it is not, as in that species, inflected into the 
groove : the groove is here rather an open slit, always on the 
sinister margin (looking from the axis of the fruit), and is sur- 
rounded by a thick callous rim, which, rising from the basal 
and hilar point of attachment of the seed, extends upwards to 
one-third or half its length. This crustaceous coating lies close 
upon the intermediate integument of the seed over its two broad 
faces ; but at its summit, and all along the other margin (oppo- 
site to that of the groove), a vacant space intervenes between 
them. The raphe is imbedded in that intermediate integument 
in the form of a simple cord, the thicker moiety of which runs 
along the base of the groove, and is free from it at all points, 
except at the bottom of the groove, where it adheres to it by 
means of a crustaceous deposit : it continues its course in a 
peripherical direction, crossing the apical chalaza beneath the 
free space mentioned, and runs down along the opposite margin 
of the seed, till it again reaehes the pointed base or micropylar 
extremity of the inner integument. I have frequently succeeded 
in detaching the entire raphe with a portion of the integument 
in which it is imbedded (even from over the chalaza), when it 
thus appears in one unbroken peripherical band, containing 
spiral vessels : this separation of the raphe may be efiected with- 
out disturbing the under or more internal integument, showing 
that it has no adhesion to it*. 
A very similar structure is found in Rhamnus utilis, Dene. : 
here the embryo, the albumen, and the two integuments, are 
folded on one another exactly as in R. chlorophorus, the groove 
being, in like manner, constantly on the same sinister margin ; 
Complete details of this organization are given in Plate 33 b. 
