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Show 144 HETEROSTYLED TRIMORPHIC PLANTS. CHAP. IV· exa1nined. Some artificially fertilised short- and longstyled capsules produced a greater number of seeds than was ever observed by me in wild plants of the same forms, but then I did not examine many of the latter. This plant, I may add, offers a remarkable instance, how profoundly ignorant we are of the life-conditions of a species. Naturally it grows "in wet ditches, watery places, and especially on the banks of streams," and though it produces so many minute seeds, it never spreads on the adjoining land; yet, when planted in my garden, on clayey soil 1 ying over chalk, and which is so dry that a rush cannot be found, it thrives luxuriantly, grows to above 6 feet in height, produces self-sown seedlings, and (which is a severer test) is as fertile as in a state of nature. Nevertheless it would be almost a miracle to find this plant growing spontaneously on such land as that in my garden. According to V aucher and Wirtgen, the three forms coexist in all parts of Europe. Some friends gathered for me in North Wales a number of twigs from separate plants growing near one another, and classified them. My son did the same in Hampshire, and here is the result :- TABLE 22. I . I Long-styled. M1d-stylcd. Short-styled. Total. --------------------·--1---- North Wales . 95 Hampshire 53 --- Total I 148 97 38 135 72 38 110 264 129 393 If twice or thrice the number had been collected, the three forms would probably have been found nearly equal; I infer this from considering the above figures, and from my son telling me that if he had CHAP. IV. LYTHRUM SALICARIA. 145 collected in another spot, he felt sure that the midstyled plants would have been in excess. I several times sowed small parcels of seed, and raised all three forms;. but. I negl~cted to record the parent-form, except1ng In one Instance, in which I raised from short-styled seed tw~lve plants, of which only one turned out long-styled, four mid-styled, and seven short-sty led. Two plants of each form were protected from the access of insects during two successive years, and in the autumn they yielded very few capsules and presented a remarkable contrast with the adjoining uncovered plants, which were densely covered with capsules. In 1863 a protected long-styled plant produced only five poor capsules; two mid-styled plants produced together t~e same number; and two· short-styled plants only a Single one. These capsules contained very few seeds; yet the plants were fully productive when artificially fertilised under the net. In a state of nature the flowers are incessantly visited for their nectar by hiveand other bees, various Diptera and Lepidoptera.* The nectar is secreted all round the base of the ovarium · but a passage is formed along the upper and inner' side of the flower by the lateral deflection (not represented in the diagram) of the basal portions of the ~l~~ents; so that insects invariably alight on the proJecting stamens and pistil, and insert their proboscides along the upper and inner margin of the corolla. We can now see why the ends of the stamens with their anthers, and the ends of the pistils with their stigmas, * H. Muller gives a list of the species, ' Die Befruch tung der Blumen,' p. 196. It appears that one bee, the Cilissa melanura, almost confines its visits to thi~ plant. L |