. The principles of botany, as exemplified in the phanerogamia. Botany; Botany; Phanerogams; 1854. rERTILIZATION. 165 one and then the other approaching the pistil and discharging upon it the polliniferous contents of their anthers. When grains of pollen are thrown on water, the absorption of the fluid is so rapid, that they burst, and a thick liquid escapes from them which spreads itself over the surface of the water. This thick liquid, in fig. 69, is seen escaping from one Tig. of the pollen grains of Ipomoea hederacea, and is the fecundating matter of the grain. The action of the polle
. The principles of botany, as exemplified in the phanerogamia. Botany; Botany; Phanerogams; 1854. rERTILIZATION. 165 one and then the other approaching the pistil and discharging upon it the polliniferous contents of their anthers. When grains of pollen are thrown on water, the absorption of the fluid is so rapid, that they burst, and a thick liquid escapes from them which spreads itself over the surface of the water. This thick liquid, in fig. 69, is seen escaping from one Tig. of the pollen grains of Ipomoea hederacea, and is the fecundating matter of the grain. The action of the pollen is therefore liable to be frustrated by wet weather. This evil is guarded against by the property which the anther-cells possess of open- ing only in fine weather, as well as by the action of the floral envelopes, which in some plants appear to be exceedingly hygrometrical, enveloping the sexual organs on the slightest appearance of any humidity in the atmosphere. The flowers of the red ohiokweed (Anagallis) are a very remarkable illus- tration of this phenomena. In this view too the economy of various aquatic plants is exceedingly interesting, as for instance the pondweeds (Pota- mogeton.) These plants live wholly submerged in the water; but at the time of flowering, the peduncles or flower stalks elongate so as to raise their flowers to the surface on which they may be seen floating. The act of fertilization is thus accomplished in the open air, and the ovaries are again drawn beneath the water, where the seed ripens. The peduncles of 15. 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 Coultas, Harland, d. 1877. Philadelphia : King & Baird
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Keywords: ., bookcentury1800, bookdecade1850, booksubjectbotany, bookyear1854
