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Show 86 FLOWERS ON SAME PLANT CROSSED. CHAP. III. TABLE XXIV. N.B. 0 signifies that the Plant died, or did not produce a Flowerstem. Plants rai::;ed from a Plants raised from Cross between dif- No. of Pot. Fluwers fertilised ferent Flowers on the w ith th(·ir own Pollen. same Plant. - - --·--- Inches. Inches. I. 49~ 4-5~ 46~ 52 43§ 0 II. 38~ 54~ 47~ 47 g 0 32~ IJI. 54~ 46g - - IV. 32~ 41 ~ 0 29~ 43~ 37 ~ v. 46H 42~ 40~ 42~ 43 0 VI. 48§ 47~ 46~ 48~ - VII. 48~ 25 42 40~ -- VIII. 46~ 39~ IX. 49 30~ Crowded Plants. 50~ 15 46~ 36~ 47 a 44~ 0 31§ X. 46~ 47~ Crowded Plants. 35~ 0 24~ 34~ 41~ 40~ 11 H 41~ Total inches. 1078•00 I 995·38 CHAP. III. OALOEOLARIA. The average height of the flower-stems on the twenty-five crossed plants in all the pots taken together is 43 ·12 inches, and that of the twenty-five self-fertilised plants 39 · 82, or as 100 to 9:J. In order to test this result, the plants planted in pairs in Pots I. to VIII. were considered hy themselves, and the average height of the sixteen cros~ed plants is here 44 · 9, and that of tho sixteen self-fertilised plants 4~ · 03, or as 100 to 94. Again, the plants raised from the thickly sown seed in Pots IX. and X., which were sul~ecten to very severe mutual competition, were taken by themselves, and the average height of the nine cro~sod plants is 39 · 86, and that of the nine self-fertilised plants 35 · 88, or as 100 to 90. The plants in these two latter pots (IX. and X.), after being measured, were cut down close to tho ground and weighed : the nine crossed plants weighed 57· 66 ounces, and the nino self-fertilised plants 45 · 25 ounces, or as 100 to 78. On the whole we may conclude, especially from the evidence of weight, that seedlings from a cross between flowers on the same plant have a decided, though not great, advantage over those from flowers fertilised with their own pollen, more especially in the case of the plants subjected to severe mutual competition. But the advantage is much less than that exhibited by the crossed offspring of distinct plants, for these exceeded the selffertilised plants in height as 100 to 70, and in the number of flower-stems as 100 to 48. Digitalis thus differs from Ipomma, and almost certainly from Mimulus, as with these two species a cross between flowers on the same plant did no good. 0ALOEOLARIA. A bushy greenhouse variety, with yellow flowm·s blotched with purple. The flowers in this genus are constructed so as to favour or almost ensure cross-fertilisation;* and Mr. Anderson remarks t that extreme care is necessary to exclude insects in order to preserve any kind true. He adds the interesting statement, that when the corolla is cut quite away, insects, as far as he has seen, never discover or visit the flowers. This plant is, however, selffertile if insects are excluded. So few experiments were made by me, that they are hardly worth giving. Crossed and self-fertilised seeds were sown on opposite sides of a pot, and * Hildebrand, as quoted by H. MiiJle1·, 'Die Befruchtung der Blumen,' 1873, p. 277. t 'Gardeners' Chronicle,' 1853, p. _534. |