CHAP. II. 
EMBRYO. 
215 
embryo as to be undistinguishable, but is indicated externally 
by a little slit above the base (Plate VI. fig. 6. B. e), within 
which it lies until called into development by germination. 
The exceptions to what has been now described ought, 
like those of dicotyledons, rather to be called remarkable 
modifications. Much stress has been laid upon them by se- 
veral writers, who have thought it requisite to give particular 
names to their parts. To me, however, it appears far more 
advisable to explain their analogies without the unnecessary 
creation of new and bad names. In Graminece (Plate VI. 
fig. 4.) the embryo consists of a lenticular body lying on the 
outside of the base of the albumen on one side, and covered 
on its inner face by that body, and on its outer face by the 
testa : if viewed on the face next the testa, a slit will be 
observed of the same nature as that in the side of the 
embryo of Aroideae ; opening this cleft a small conical pro- 
jection is discovered, pointing towards the apex of the seed. 
If the embryo be then divided vertically through the conical 
projection, it will be seen that the latter (c) is a sheath includ- 
ing other little scales resembling the rudiments of leaves ; that 
that part of the embryo which lies next the albumen (<i), and 
above the conical body, is solid ; and that the lower extremity 
of the embryo [e) contains within it the indication of an in- 
. ternal radicle, as in other monocotyledons. In this embryo 
it is to be understood that the conical projection is the plu- 
mule ; that part of the embryo lying between it and the 
albumen, a single scutelliform cotyledon ; and the lower point 
of the embryo, the radicle. In wheat there is a second small 
cotyledon on the outside of the embryo, inserted a little lower 
down than the scutelliform cotyledon. This last is called 
scutellum by Gaertner, who considered it of the nature of 
vitellus. Richard considered the scutelliform cotyledon a par- 
ticular modification of the radicle, which he called hypohlastus; 
the plumule a form of cotyledon, called hlastus ; the anterior 
occasional cotyledon a peculiar appendage, named epiblastus ; 
and the radicle a protuberance of the caulicule, called radicu- 
loda. He, further, in reference to this peculiar opinion, 
termed embryos of this description macropodous. In these 
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