Endosperm at _a_, _a_; cotyledons at _b_.] [Illustration: FIG. 23.—GERMINATION COMPLETE IN CASTOR BEAN. ] =Germination of Monocotyledons.=—Thus far we have studied dicotyledonous seeds; we may now consider the monocotyledonous group. Soak kernels of corn. Note that the micropyle and hilum are at the smaller end (Fig. 24). Make a longitudinal section through the narrow diameter; Fig. 25 shows it. The single cotyledon is at _a_, the caulicle at _b_, the plumule at _p_. The cotyledon remains in the seed. The food is stored both in the cotyledon and as endosperm, chiefly the latter. The emerging shoot is the plumule, with a sheathing leaf (_p_, Fig. 26). The root is emitted from the tip of the caulicle, _c_. The caulicle is held in a sheath (formed mostly from the seed-coats), and some of the roots escape through the upper end of this sheath (_m_, Fig. 26). The epicotyl elongates, particularly if the seed is planted deep or if it is kept for a time confined. In Fig. 27 the epicotyl has elongated from _n_ to _p_. The true plumule-leaf is at _o_, but other leaves grow from its sheath. In Fig. 28 the roots are seen emerging from the two ends of the caulicle-sheath, _c_, _m_; the epicotyl has grown to _p_; the first plumule-leaf is at _o_. [Illustration: FIG. 24.—SPROUTING INDIAN CORN. Hilum at _h_; micropyle at _d_.] [Illustration: FIG. 25.—KERNEL OF INDIAN CORN. Caulicle at _b_; cotyledon at _a_; plumule at _p_.] [Illustration: FIG. 26.—INDIAN CORN. Caulicle at _c_; roots emerging at _m_; plumule at _p_.] [Illustration: FIG. 27.—INDIAN CORN. _o_, plumule; _n_ to _p_, epicotyl.] In studying corn or other fruits or seeds, the pupil should note how the seeds are arranged, as on the cob. Count the rows on a corn cob. Odd or even in number? Always the same number? The silk is the style: find where it was attached to the kernel. Did the ear have any coverings? Explain. Describe colours and markings of kernels of corn; and of peas, beans, castor bean. [Illustration: FIG. 28.—GERMINATION IS COMPLETE. _p_, top of epicotyl; _o_, plumule-leaf; _m_, roots; _c_, lower roots.] =Gymnosperms.=—The seeds in the pine cone, not being inclosed in a seed vessel, readily fall out when the cone dries and the scales separate. Hence it is difficult to find cones with seeds in them after autumn has passed (Fig. 29). The cedar is also a gymnosperm. Remove a scale from a pine cone and draw it and the seeds as they lie in place on the upper side of the scale. Examine the seed, preferably with a magnifying glass. Is there a hilum? The micropyle is at the bottom or little end of the seed. Toss a seed upward into the air. Why does it fall so slowly? Can you explain the peculiar whirling motion by the shape of the wing? Repeat the experiment in the wind. Remove the wing from a seed and toss it and an uninjured seed into the air together. What do you infer from these experiments? [Illustration: FIG. 29.—CONES OF HEMLOCK (ABOVE), WHITE PINE, PITCH PINE. ]