side of the
albumen. 53. Embryo detached; showing the very broad and leaf-like
cotyledons, applied face to face, and the pair incurved.]

[Illustration: Fig. 54. Embryo of Abronia umbellata; one of the
cotyledons very small. 55. Same straightened out.]

38. =Polycotyledonous= is a name employed for the less usual case in
which there are more than two cotyledons. The Pine is the most familiar
case. This occurs in all Pines, the number of cotyledons varying from
three to twelve; in Fig. 56, 57 they are six. Note that they are all on
the same level, that is, belong to the same node, so as to form a circle
or _whorl_ at the summit of the caulicle. When there are only three
cotyledons, they divide the space equally, are one third of the circle
apart. When only two they are 180 deg. apart, that is, are _opposite_.

39. The case of three or more cotyledons, which is constant in Pines and
in some of their relatives (but not in all of them), is occasional among
Dicotyls. And the polycotyledonous is only a variation of the
dicotyledonous type,--a difference in the number of leaves in the whorl;
for a pair is a whorl reduced to two members. Some suppose that there
are really only two cotyledons even in a Pine embryo, but these divided
or split up congenitally so as to imitate a greater number. But as
leaves are often in whorls on ordinary stems, they may be so at the very
beginning.

[Illustration: Fig. 56. Section of a Pine-seed, showing its
polycotyledonous embryo in the centre of the albumen, moderately
magnified. 57. Seedling of same, showing the freshly expanded six
cotyledons in a whorl, and the plumule just appearing.]

40. =Monocotyledonous= (meaning with single cotyledon) is the name of
the one-cotyledoned sort of embryo. This goes along with peculiarities
in stem, leaves, and flowers, which all together associate such plants
into a great class, called MONOCOTYLEDONOUS PLANTS, or, for shortness,
MONOCOTYLS. It means merely that the leaves are alternate from the very
first.

[Illustration: Fig. 58. Section of a seed of the Iris, or
Flower-de-Luce, enlarged, showing its small embryo in the albumen, near
the bottom. 59. A germinating seedling of the same, its plumule
developed into the first four leaves (alternate), the first one
rudimentary, the cotyledon remains in the seed.]

41. In Iris (Fig. 58, 59) the embryo in the seed is a small cylinder at
one end of the mass of the albumen, with no apparent distinction of