. A text-book of botany for secondary schools. Botany. FLOWERS AND INSECTS 247 the several stamens and the single carpel are in a cluster enclosed in-a boat-shaped structure (keel) formed by two of the-petals (Fig. 241). The stigma is at the summit of the style and projects somewhat beyond the pollen sacs, some of whose pollen lodges on a hairy zone on the style below the stigma. While the stigma is not alto- gether secure from receiving some pollen, the position does not favor it. The projecting keel is the nat- ural landing place for a bee visiting the flower; and it is so inserted that the
. A text-book of botany for secondary schools. Botany. FLOWERS AND INSECTS 247 the several stamens and the single carpel are in a cluster enclosed in-a boat-shaped structure (keel) formed by two of the-petals (Fig. 241). The stigma is at the summit of the style and projects somewhat beyond the pollen sacs, some of whose pollen lodges on a hairy zone on the style below the stigma. While the stigma is not alto- gether secure from receiving some pollen, the position does not favor it. The projecting keel is the nat- ural landing place for a bee visiting the flower; and it is so inserted that the weight of the insect depresses it, and the stig- ma comes in contact with its body. Not only does the stigma strike the body, but by the glan- cing blow the surface of the style is rubbed against the insect; and upon this style, below the stigma, the pollen has been shed and is rubbed off against the insect. At the next flower visited the »tigma is likely to strike the pol- len obtained from the pre- vious flower, and the style will deposit a new supply of pollen. It is interesting to press down slightly the keel of such a flower and see the style apparently dart out. In the iris or common flag, each stamen is in a kind of pocket between the petal and the petal-like style; while the stigmatic surface is on the top of a flap or shelf which 17. Fig. 242.—Longitudinal section of flower of iris, showing a single stamen between the drooping petal and the petal-like style; the stigmatic shelf is seen above the stamen, at the top of the style; the nectar pit is at the junction of petal and stamen. —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
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectbotany, bookyear1906
