. Scientific lectures. Science; Natural history; Archaeology. 28 ON FLOWERS AND INSECTS. [lect. As the type of another class of cases in which two kinds of flowers are produced by the same species (though not on the same stock) we may take our common Cow- slips and Primroses. If you examine a number of them, you will find that they fall into two distinct series. In some of the flowers, the pistil is as long as the tube, and the button-shaped stigma (Fig. 31, st) is situated at the mouth of the flower; the stamens (a a) being: half-way down the tube : while in the other set, on the contrary, th
. Scientific lectures. Science; Natural history; Archaeology. 28 ON FLOWERS AND INSECTS. [lect. As the type of another class of cases in which two kinds of flowers are produced by the same species (though not on the same stock) we may take our common Cow- slips and Primroses. If you examine a number of them, you will find that they fall into two distinct series. In some of the flowers, the pistil is as long as the tube, and the button-shaped stigma (Fig. 31, st) is situated at the mouth of the flower; the stamens (a a) being: half-way down the tube : while in the other set, on the contrary, the anthers are at the mouth of the flower, and the. X 2SO Fig. 81.—Primula (long-styled form). Fig. 32.—Primula (short-styled form). stigma half-way down. The existence of these two kinds of flowers had long been known, but it remained unexplained until Mr. Darwin devoted his attention to the subject. Now that he has furnished us with the clue, the case is clear enough. An insect visiting a plant of the short-styled form would dust its proboscis at a certain distance from the extremity (Fig. 32, a), which, when the insect passed to a long-styled flower, would come just opposite to the pistil (Fig. 31, st). At the same time, the stamens of this second form (Fig. 31, a) would dust the proboscis at. 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 Lubbock, John, Sir, 1834-1913. London, New York, Macmillan and Co.
Size: 2207px × 1133px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, booksubjectarchaeology, booksubjectnaturalhisto
