. Notes on the life history of British flowering plants. Botany; Plant ecology. 278 BRITISH FLOWERING PLANTS chap. fly, the weight of which presses down the lower Hp, and thus opens the way to the honey. As in Antir- rhinum the pistils and stamens lie close underneath the upper lip. The pistil consists of two lobes—an upper one, quite short and pointed; and a lower one, which is longer, spathulate, and bears the stigma on its upper surface (Fig. 175). The stigma projects beyond the anthers, so that it is first touched by any entering insect. The anthers open downwards, so that the head of the
. Notes on the life history of British flowering plants. Botany; Plant ecology. 278 BRITISH FLOWERING PLANTS chap. fly, the weight of which presses down the lower Hp, and thus opens the way to the honey. As in Antir- rhinum the pistils and stamens lie close underneath the upper lip. The pistil consists of two lobes—an upper one, quite short and pointed; and a lower one, which is longer, spathulate, and bears the stigma on its upper surface (Fig. 175). The stigma projects beyond the anthers, so that it is first touched by any entering insect. The anthers open downwards, so that the head of the insect necessarily touches them and takes up a fresh supply of pollen. The stigmatic surface, as already mentioned, is on the upper side of the stigma, and lies, therefore, against the upper lip of the Fig. 178.— Ulricularia vulgaris. Mouth of bladder, seen sideways, a, antenna ; b, strengthened margin of fore-court; c, flap. When the flower opens, however, it turns downwards (Fig. 175) so as to touch the head of any insect visitor. It is, moreover, sensitive, and as soon as it is touched it rises again, and resumes its original position, so that the retreating insect cannot dust it with any of its own pollen. The edge of the stigma is furnished with a row of hairs, which, according to Heinsius,^ serve to brush the pollen from the head of the visitor. The pollen grains lend themselves to this, being provided with several longitudinal ridges. The visitors appear to be especially flies belonging to the family Syrphidse. The flowers of U. minor and U. intermedia are formed on the same general plan. In autumn most of the plant decays away, but the ' Bot. Jaarb. iv. (1892).. 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. , Ltd.
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