=Germination of Castor Bean.=--In the castor bean the hilum and micropyle are at the smaller end (Fig. 20). The bean “comes up” with a loop, which indicates that the hypocotyl greatly elongates. On examining germinating seed, however, it will be found that the cotyledons are contained inside a fleshy body, or sac (_a_, Fig. 21). This sac is the endosperm. Against its inner surface the thin, veiny cotyledons are very closely pressed, absorbing its substance (Fig. 22). The cotyledons increase in size as they reach the air (Fig. 23), and become functional leaves. [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.] =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. 28.--GERMINATION IS COMPLETE. _p_, top of epicotyl; _o_, plumule-leaf; _m_, roots; _c_, lower roots.] 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 colors and markings of kernels of corn; and of peas, beans, castor bean. =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. [Illustration: FIG. 29.--CONES OF HEMLOCK (ABOVE), WHITE PINE, PITCH PINE.]