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Show MIMULUS LUTEUS. CHAP. III. 72 The effects of a Cross with a disfi~ct Stock.- Some flowers on the self-fertilised plants in Pot IV. in Table :XI:X. were fertilised with their own pollen, and plants of the eighth self-fertilised generation were thus raised, merely to serve as parents in the following experiment. Several flowers on these plants were allowed to fertilise themselves spontaneowly (insects being of course excluded), and the plants raised from these seeds formed the ninth self-fertilised generation; they consisted wholly of the tall white variety with crimson blotches. Other flowers on the same plants of the eighth self-fertilised generation were crossed with pollen taken from another plant of the same lot; so that the seedlings thus raised were the offspring of eight previous generations of self-fertilisation with an intercross in the last generation; these I will call the irdenrossed plants. Lastly, other flowers on the same plants of tho eighth self-fertilised generation were crossed with pollen taken from plants which had been raised from seed procured from a garden at Chelsea. Tho Chelsea plants bore yellow flowers blotched with red, but differed in no other respect. They had been grown out of doors, whilst mine had been cultivated in pots in the greenhouse for the last eight generations, and in a different kind of soil. The seedlings raised from this cross with a wholly different stock may be called the " Chelsw-crossed." The three lots of seeds thllll obtained were allowed to germinate on bare sand; and whenever a seed in all three lots, or in only two, germinated at the same time, th<ly were planted in pots superficially divided into three or two compartments. The remaining seeds, whether or not in a state of germination, were thickly sown in three divisions ina large pot, :X., in TILble X:X. When the plants had grown to their full height they were measured, as shown in the following table; but only the three tallest plants in each of the three divisions in Pot X. were measured. In this table the average height of the twenty-eight Chelsea· crossed plants is 21 · 62 inches; that of the twenty-seven inter· crossed plants 12 · 2 ; and that of the nineteen self-fertilised 10 · 44. But with respect to the latter it will be the fairest plan to strike out two dwarfed ones (only 4 inches in height), so as not to exaggerate the inferiority of the self-fertilised plants; and this will raise the average height of the seventeen remaining self-fertilised plantll to 11·2 inches. Therefore the Chelsea-crossed arc to the inter· crossed in height as 100 to 56; the Chelsea-crossed to the self· fertilised as 100 to 52; and the intercrossed to the self-fertilised CHAP. III. CHOSS WITH A FRESH STOCK. 73 TABLE XX. -·I ,_ No. of Put. Plants from Selffertilised Plants of th~ Eighth GeneratiOn crossed by Chelsea Plants. .Pla?t~ from an in- elf-fertilised tetct;,ss between Plants of the Ninth t.~e llants of the Generation from ~t ghth elf-ferti- _Plants of the hsed Generation. ~tgbth Self-fertilised Generation. I. ln<'hes. 30~ 28~ Inches. 14 1 3~ ... ---1---·-· --1--1_3:~. ~ II. - III. IV. v. VI. 12§ 9 ~ 8l'l 9 11 11 ~ 12~ 8~ 11 ~ 6' ll 4 13 ~ 11-g 12 16~ - VII. 18g 7 12 g4 - --~-l ___:__ j_ _ ____:·_·: _- 12~ 15 24~ 12"~ 20~ 11 ~ -· - -1- 26~ 15~ VIII. -----1 ---~- 17 ~ 226 27g - IX. :32g 11~ 6 17 ____20 ~ 14~ .... - - -- 18k 9§ 16g 82g X. Crowded Plants. 17 R 10 I - -----~~-------- Total inches. 605•38 329•50 |