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Show 336 SELF-STERILE PLANTS. CHAP. IX. two seeds, which germinated well. A large number of the stigmas on several of the other co~·ymbs were re· peatedly smeared with pollen from then own :·orymb; ·but they yielded only five very poor ~eeds, 'vhich were incapable of germination. Th.er~fore the above th.ree plants belonging to two vanetles, thou~h growing vigorously and fertile with polle~ fro~n either of. the other two plants, were utterly stenle with pollen from other flowers on the same plant. Reseda odorata.-Having observed that certain in-dividuals were self-sterile, I covered during the sun1mer of 1868 seven plants under separate nets, and will call these plants A, B, 0, D, E, F, G. They all appeared to be quite sterile with their own pollen, but fertile with that of any other plant. Fourteen flowers on A were crossed with pollen fro1n B or 0, and produced thirteen fine capsules. Sixteen flowers were fertilised with pollen fron1 other flowers on the same plant, but yielded not a single capsule. Fourteen flowers on B were crossed with pollen from A, 0, or D, and all produced capsules; some of these were not very fine, yet they contained plenty of seeds. Eighteen flowers were fertilised with pollen from other flowers on the same plant, and produced not one capsule. Ten flowers on C were crossed with pollen from A, B, D, or E, and produced nine fine capsules. Nineteen flowers were fertilised with pollen fro1n other flowers on the sa1ne plant, and produced no capsules. Ten flowers on D were crossed with pollen from .l\ .. , B, 0, or E, and produced nine fine capsules. Eio-hteen flowers were fertilised with pollen fr01n other flo~ers on the sa1ne plant, and produced no capsules. Seven flowers on E were crossed with pollen from CHAP. IX. SELF-STERILE PLANTS. 337 A, 0, or D, and all produced fine capsules. Eight flowers were fertilised with pollen from other flow rs on the same plant, and produced no capsules. On the plants F and G no flowers were crossed, but very Inany (nlunber not recorded) were fertilised with pollen from other flowers on the sa1ne plants, and these did not produce a single capsule. We thus see that fifty-five flowers on five of the above plants were reciprocally crossed in various ways; s~veral. flowers on each of these plants being fertihsed with pollen fron1 several of the other plants. These fifty-five ~owers produced fifty-two capsules, ahnost all of wh1ch were of full size and contained an abundance of seeds. On the other hand seventv~ in~ .flower~ (besides many others not recorded) we~·e fertilised with pollen fro1n other flowers on the same plants, and these ·did not produce a single capsule. In one case in which I examined . the stigmas of the flowers fertilised with their own pollen, these were pen~trated by the pollen-tubes, although such penetration p~oduced no effect. Pollen falls generally, and I beheve always, fron1 the anthers on the stign1as of the same flower; yet only three out of the above seven protected plants produced spontaneously any capsules, and these it might have been thought must have been self-fertilised. There were altogether seven such capsu.les; but as they were all seated close to the artificially crossed flowers, I can hardly doubt that a few grains of foreign pollen had accidentally fallen on their stigmas. Besides the above seveu plants, four others were kept covered under the same large ~et; and so1ne of these produced here and there In the most caprieious manner little groups of capsules; and this makes 1ne believe that a bee, many of which settled on the outside of the net beina ' b z |