. The elements of botany for beginners and for schools. Plants. 22 SEEDLINGS. [section 3. whole surface. Tt supplements the nutritive matter contained in the embryo. Both together form no large store, but sufficient for establishing the seedling, with tiny root, stem, and pair of leaves for initiating its independent growth; which in due time proceeds as in Pig. 44, 45. 34. Smaller embryos, less developed in the seed, are more dependent upon the extraneous supply of food. The figures 46-53 illustrate four. grades in this respect. The smallest, that of the Peony, is still large enough to be see
. The elements of botany for beginners and for schools. Plants. 22 SEEDLINGS. [section 3. whole surface. Tt supplements the nutritive matter contained in the embryo. Both together form no large store, but sufficient for establishing the seedling, with tiny root, stem, and pair of leaves for initiating its independent growth; which in due time proceeds as in Pig. 44, 45. 34. Smaller embryos, less developed in the seed, are more dependent upon the extraneous supply of food. The figures 46-53 illustrate four. grades in this respect. The smallest, that of the Peony, is still large enough to be seen with a hand magnifying glass, and even its cotyledons may be discerned by the aid of a simple stage microscope. 35. The broad cotyledons of Mirabilis, or Tour-o'clock (Fig. 52, 53), with the slender caulicle almost encircle and enclose the floury albumen, instead of being enclosed in it, as in the other illustrations. Evidently here the germinating embryo is principally fed by one of the leaf-like coty- ledons, the other being out of contact with the supply. In the embryo of Abronia (Fig. 54, 55), a near relative of Mirabilis, there is a singular modification; one cotyledon is almost wanting, being reduced to a rudi- ment, leaving it for the other to do the work. This leads to the question of the 36. Number of Cotyledons. In all the preceding illustrations, the embryo, however different in shape and degree of development, is evidently Fig. 44. Seedling of Morning Glory more advanced (root cut away); cotyledons well developed into foliage-leaves: succeeding internode and leaf well developed, and the next forming. 45. Seedling more advanced; reduced to much below natural Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Gray, Asa, 1810-1888. New York : American Book Company
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectplants, bookyear1887
