the more
correct one, for it is the initial stem, which merely gives origin to
the root), as to its position in the seed, always points to and lies
near the micropyle. In relation to the pericarp it is

_Superior_, when it points to the apex of the fruit or cell, and

_Inferior_, when it points to its base, or downward.

[Illustration: Fig. 424. Embryo of Calycanthus; upper part cut away, to
show the convolute cotyledons.]

390. =The Cotyledons= have already been illustrated as respects their
number,--giving the important distinction of _Dicotyledonous_,
_Polycotyledonous_ and _Monocotyledonous_ embryos (36-43),--also as
regards their thickness, whether _foliaceous_ or _fleshy_; and some of
the very various shapes and adaptations to the seed have been figured.
They may be straight, or folded, or rolled up. In the latter case the
cotyledons may be rolled up as it were from one margin, as in
Calycanthus (Fig. 424), or from apex to base in a flat spiral, or they
may be both folded (_plicate_) and rolled up (_convolute_), as in Sugar
Maple (Fig. 11.) In one very natural family, the Cruciferae, two
different modes prevail in the way the two cotyledons are brought round
against the radicle. In one series they are

_Accumbent_, that is, the edges of the flat cotyledons lie against the
radicle, as in Fig. 425, 426. In another they are

[Illustration: Fig. 425. Seed of Bitter Cress, Barbarea, cut across to
show the accumbent cotyledons. 426. Embryo of same, whole.]

_Incumbent_, or with the plane of the cotyledons brought up in the
opposite direction, so that the back of one of them lies against the
radicle, as shown in Fig. 427, 428.

[Illustration: Fig. 427. Seed of a Sisymbrium, cut across to show the
incumbent cotyledons. 428. Embryo of the same, detached whole.]

391. As to the situation of the embryo with respect to the albumen of
the seed, when this is present in any quantity, the embryo may be
_Axile_, that is occupying the axis or centre, either for most of its
length, as in Violet (Fig. 429), Barberry (Fig. 48), and Pine (Fig. 56);
and in these it is straight. But it may be variously curved or coiled in
the albumen, as in Helianthemum (Fig. 430), in a Potato-seed (Fig. 50),
or Onion-seed (Fig. 60), and Linden (Fig. 414); or it may be coiled
around the outside of the albumen, partly or into a circle, as in
Chickweed (Fig. 431, 432) and in Mirabilis (Fig. 52). The latter mode
prevails in Campylotropous seeds. I