. Textbook of botany. Botany. THE INDIAN CORN 163. sists of a radicle, which is turned toward the base of the kernel, and a plunmle, which is turned upward. The plumule bears several small secondary leaves. Wrapped about the radicle and plumule is a single broad, thick seed leaf (instead of the two seed leaves of the bean); this seed leaf separates the radicle and plumule on the inner side from the endosperm, and covers them on the outer side also, except for a very narrow strip. The wall of the ovary, which becomes the fruit coat (corresponding to the pod of the bean), remains thin and comes
. Textbook of botany. Botany. THE INDIAN CORN 163. sists of a radicle, which is turned toward the base of the kernel, and a plunmle, which is turned upward. The plumule bears several small secondary leaves. Wrapped about the radicle and plumule is a single broad, thick seed leaf (instead of the two seed leaves of the bean); this seed leaf separates the radicle and plumule on the inner side from the endosperm, and covers them on the outer side also, except for a very narrow strip. The wall of the ovary, which becomes the fruit coat (corresponding to the pod of the bean), remains thin and comes to be very closely united with the seed coat. Thus the corn kernel is a fruit containing a single seed; but, because the fruit coat and seed coat have grown so closely together, it is only by studying the way in which the kernel has developed from the ovary of the flower that we can make sure that the outer covering of the kernel is really something more than a seed coat. At or near the free end of the kernel and on its upper side (that is, on the side turned toward the tip of the ear) is a small, sharp projection. This is the style ; the stigma (silk) dried and withered after pollination but still remains at- tached to the style. The end of the kernel that is attached to the ear corresponds, of course, to the base of the ovary. Near this place are the micropyle and the point of attach- ment of the ovule within the ovary. But since these points are both covered by the fruit coat they cannot be seen from Fig. 102. —A, z. side view of a kernel of Indian corn, with a portion of the fruit coat and seed coat removed so as to show the position of the embryo. B, a lengthwise section of a kernel, cut through the embryo; a, style; b, horny endosperm; c, starchy endosperm; d, plumule, with sec- ondary leaves; e, thick seed leaf, wrapped about the rest of the embryo; /, radicle; g, point at which the kernel was attached to the Please note that these images are extracted from scann
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1917
