. Plant studies; an elementary botany. Botany. SPEKMATOPHYTES : ANGIOSPEEMS 361 simple, being developed entirely within the spores which produce them. The male gametophyte is represented by a few cells which appear within the pollen grain, two of which are male cells. When pollination occurs, and the pollen has been transferred from the pollen-sacs to the stigma, it is de- tained by the minute papilla? of the stig- matic surface, which also excretes a sweet- ish sticky fluid. This fluid is a nutrient so- lution for the micro- spores, which begin to put out their tubes. A pollen-tube penetrates
. Plant studies; an elementary botany. Botany. SPEKMATOPHYTES : ANGIOSPEEMS 361 simple, being developed entirely within the spores which produce them. The male gametophyte is represented by a few cells which appear within the pollen grain, two of which are male cells. When pollination occurs, and the pollen has been transferred from the pollen-sacs to the stigma, it is de- tained by the minute papilla? of the stig- matic surface, which also excretes a sweet- ish sticky fluid. This fluid is a nutrient so- lution for the micro- spores, which begin to put out their tubes. A pollen-tube penetrates through the stigmatic surface, enters among the tissues of the style, which is sometimes very long, slowly or rapidly traverses the length of the style sup- plied with food by its cells but not penetrat- ing them, enters the cavity of the ovary, passes through the micropyle of an ovule, penetrates the tissues of the nucellus (if any), and finally reaches and pierces the wall of the embryo-sac, within which is the egg awaiting fertilization (Fig. 327).. Fig. 327. Diagram of a longitudinal Bection through a carpel, to illustrate fertilization with all parts in place: s. stigma ; g, style ; o, ovary ; ai. ii, outer and inner integuments ; n, base of nucel- lus ; /. funiculus ; b, antipodal cells : c, endo- sperm nucleus ; h, egg and one synergid : p. pol- len-tube, having grown from stigma and passed through the micropyle (m) to the egg.—After 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 Coulter, John Merle, 1851-1928. New York, D. Appleton and Company
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