| OCR Text |
Show 190 PETUNIA VIOLACEA. CHAP. VI. Three capsules were obtained by crossing flowers .on the above crossed plants, and three other capsules by again selfff- lrtilising flowers on the self-fertilised plants. One of the latter ca sules appeared as fino as any. one of the crossed capsules; b!t the other two contained many Imperfect. seeds. Fr~m theso two lots of seeds the plants of the following generatwn were raised. a1·ossed and self-fertilised Plants ofthe Second Generrdion.-As in the last generation, many of the self-fertilised seeds germinated before the crossed. Seeds in an equal state of germination were planted on the opposite sides of three pots. ~~e crossed seedlings soon greatly exceeded in height the self-fertilised. In Pot I., when the tallest crossed plant was 10~ inches high, the tallest self-fertilised was only 3~ inches; in Pot II. the exr,ess in height of. the crossed was not quite so great. The plants were treated as In the last generation and when fully grown measured as before. In Pot III. both t' he crossed plants were killed at an early age by some animal so that the self-fertilised had no competitors. Neverthe- ' . loss these two self-fertilised plants were measured, and are m-cluded in the following table. The crossed plants flowered long before their self-fertilised opponents in Pots I. and II., and before those growing separately in Pot III. TABLE LXXVII. Petunia viulacea (Second Generation). No. of Pot. Crossed Plants. Self-fertili sed Plants. - - Inches. Inches. I. 57~ 13g 36§ 8 II. 44g 33g 24 28 --· III. 0 i 4G ij 0 28 9 -- Total in inches. ~ --162•0 I 157•5 The four crossed plants average 40 · 5, and the six ~elf-fertilised 26 · 25 inches in height; or as 100 to 65. But this great inequality is in part accidental, owing to some of the self- CHAP. VI. CROSSED AND SELF-FERTILISED PLANTS. 191 fertilised plants being very short, and to one of the crossed being very tall. Twelve flowers on these crossed plants were again crossed, and eleven capsules were produced; of these, five were poor and six good; the latter contained by weight 3 · 75 grains of seeds. Twelve flowers on the self-fertilised plants were again fertilised with thei~ own pollen and produced no less than twelve capsules, and the SIX finest of these containe~ by weight 2 ·57 grains of seeds. It should however Le observed that these latter capsules were produced by the plants in Pot III., which were not exposed to any c~mpetiti~n. The seeds in the six fine crossed capsules to those 1n the SIX finest self-fertilised capsules were in weight as 100 to 68. From these seeds the plants of the next generation were raised. Crossed and sr:lf-fertilised Plunts of the Tltird Generation.-The above Eeeds were placed on sand, and after germinating were plant~~ ill pairs on the opposite sides of four pots; and all the remammg seeds were thickly sown on the two sides of a fifth large pot. The result was surprising, for the self-fertilised seedEngs very early in life beat the crossed, and at one time were nearly double their height. At first the case appeared like that of Mimulns, in which after the third generation a tall and highly self-fert!le variety appeared. But as in the two succeeding generatiOns the crossed plants resumed their former superiority over the self-fertilised, the case must be looked at as an anomalv The sole conjecture which I can form is that the crossed seed~ TABL.E LXXVIII. Petuniu violacea (Third Gene1·ation; plants very youn[J). No. of Pot. Crossed Plants. Self-fertilised Plants. Inches. Inchrs. I. 1 4 l!" 56 l!" 1 4~ II. 5~ 8~ 56l!" 6~ III. 4 5~ IV. 1 ~ 5~ - - Total in inches. 19•63 36•50 |
