. Plants and their uses; an introduction to botany. Botany; Botany, Economic. W I I ^ ic Fig. STO.—Norway Spruce. Fertilization of egs-cell. -1, ripe egg-cell with nucleus ion) and lower neck-cell (c/), V. B, same, later, the tip of a poUcn-tubc (p) having entered the egg-cell and discharged into it the male nucleus {sv) which approaches the female nucleus (ors). C, same, later, the two nuclei ha-\-ing become fused into one, which soon divides into four nuclei that move to the lower end of the egg-cell. D, lower end of the egg-cell showing two of the four nuclei which have moved into it
. Plants and their uses; an introduction to botany. Botany; Botany, Economic. W I I ^ ic Fig. STO.—Norway Spruce. Fertilization of egs-cell. -1, ripe egg-cell with nucleus ion) and lower neck-cell (c/), V. B, same, later, the tip of a poUcn-tubc (p) having entered the egg-cell and discharged into it the male nucleus {sv) which approaches the female nucleus (ors). C, same, later, the two nuclei ha-\-ing become fused into one, which soon divides into four nuclei that move to the lower end of the egg-cell. D, lower end of the egg-cell showing two of the four nuclei which have moved into it. E, same after division of the four nuclei into eight. F, same after further division has produced four tiers of nuclei, all but the uppermost four being enclosed in cell-walls. (?, same, after the middle tier of cells has elongati-d to form a suspensor which has pushed the lower tiers of cell into tiie prothallus (or endosperm) where the^- gi^'C rise, by repeated cell-division, to an eml:)r3-o which is fed by the endo- sperm. The nutritions materials left over in the endosperm when the ovule has become a y(?ed constitut(^s the sei'd-foiKl w"hich supports the \'oung phmtlet during germination. (Strasliurger.) spreading carpel, they come finally to the micropyle where ihe integument is often prolonged in such a way as to lead them directly to the tip of the nucellus. Here they germinate by forming a few cells, some of which, remaining within the spore, represent the vege- tative ]iart of the male gametojih^'te; while others, the male gametes, form a hypha-like tube which penetrates the soft tissue of the nucellus and feeds upon it like a fungus. Meanwhile the macrospore. 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 Sargent, Frederick Leroy, 1863-. New York, H. Holt and Company
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1913
