. The elements of botany for beginners and for schools. Botany. 26 SEEDLINGS. [section 3. the cereal grains) it raises the comparatively light seed into the air, the tip still remaining in the seed and feeding upon the albumen. When this food is exhausted and the seedling is well es- tablished in the soil, the upper end decays and the emptied husk of the seed faHs away. 43. In Maize or In- dian Corn (Fig. 66-70), the embryo is more de- veloped in the seed, and its parts can be made out. It lies against tlie starchy albumen, but is not enclosed therein. The larger part of it is the cotyledon, t
. The elements of botany for beginners and for schools. Botany. 26 SEEDLINGS. [section 3. the cereal grains) it raises the comparatively light seed into the air, the tip still remaining in the seed and feeding upon the albumen. When this food is exhausted and the seedling is well es- tablished in the soil, the upper end decays and the emptied husk of the seed faHs away. 43. In Maize or In- dian Corn (Fig. 66-70), the embryo is more de- veloped in the seed, and its parts can be made out. It lies against tlie starchy albumen, but is not enclosed therein. The larger part of it is the cotyledon, thickish, its edges involute, and its back in contact with the albumen; partly enclosed by it is the well-devel- oped plumule or bud which is to grow. For he cotyledon remains in the seed to fulfil its office of imbibing nourishment from the softened albu- men, which it conveys to the growing sprout; the part of this sprout which is visible is the first leaf of the plumule rolled up into a sheath and enclosing the rudiments of the succeeding leaves, at the base enclosing even the minute caulicle. In germination the first leaf of the plumule develops only as a sort of sheath, protecting the tender parts within; the second and the third form the first foliage. The caulicle never lengthens: the first root, which is formed at its lower end, or from any part of it, has to break through the enclosing sheath ; and succeeding roots soon spring from all or any of the nodes of the plumule. 44. Simple-stemmed Plants are thus built up, by the continuous pro- duction of one leaf-bearing portion of stem from the summit of the preced- ing one, beginning with the initial stem (or caulicle) in the embryo. Some Dicotyls and many Monocotyls develop only in this single line of growth (as to parts above ground) until the flowering state is approached. For some examples, see Cycas (Fig. 71, front, at the left) ; a tall Yucca or Spanish Bayonet, and two Cocoa-nut Palms behind ; at the right, a group o
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Keywords: ., bookpublishernewyorkamericanboo, booksubjectbotany, bookyear1887
