INFLORESCENCE AND FLOWERS—FRUIT AND SEED 135 
tissue, across which minute vascular bundles run from 
the embryo into the cotyledons. If the shell-like invest- 
ments described above are removed from the embryo, it 
is then possible to gently separate the cotyledons and 
see the minute plumule and radicle to which they are 
joined (fig. 36) ; on removing one cotyledon the plumule 
will be seen embedded in a slight depression at the base. 
At this point there is a little room to spare, not quite 
filled up by the radicle and plumule; a minute remnant 
of endosperm may occasionally be found here, not having 
been entirely absorbed by the developing embryo. 
The cotyledons and embryo are composed of a 
delicate epidermis enclosing the whole (fig. 37, e), and 
very thin-walled cells forming the main mass of tissue 
in which the vascular bundles run. These bundles are 
scattered in the thickness of the cotyledons, ready to 
convey fluids to and fro on germination, and already 
contain lignified vessels in the xylem and sieve-tubes in 
the phloém. 
The iso-diametric, closely-packed cells of the cotyle- 
dons are filled with reserve materials, consisting of 
large quantities of starch grains embedded in proteids 
and tannin. Here and there are scattered cells filled 
with brown pigments and containing tannin; some 
cells also contain oil-drops. Traces of sugar (quercite), 
certain bitter principles, acids, and mineral substances 
also occur in the tissues. 
