OCR Text |
Show 104 IBERIS UMBEI,LATA. . · 'fl ( . .4 of an inch) the five probably in average hmght by~ ~~0~ v~~·it right to give this case and the crossed plants. I ha\e g d sed plants proved superwr last, because h~~ the. sup~o~et Icr:~ould have assumed without dtoo uthbet tshealft- ftehreti lfiosremd eIrn h ahd eJrge a ll been crossed. As it is, I do not y know what to conclu~e.d at the two foregoing trials, I deter! 3eing much surprise in which there should be no doubt about 1nined to m. ake aIn otthheerre, fore l.ce r t.I1 I.s ed with great care (but ads the crossing. . t t -four flowers on the suppose usual without castratiOn) ~en y fon with pollen from distinct crossed plants of th~ last g:er~:e capsules. The self-fertilised plants, and thus obtained ~we y- allowed to fertilise themselves plants of the last gener~ti~~ were~lings reared from these seeds again under a. net, ~n£ til~ses~ generation. Both lots of seeds, fof rmed the thud sel - ebr d were plan ted in pairs on ·nating on are san ' d a ter ger~n . t All the remaining see s were the opposite Sides of t":"o p~ ds. f a third pot . but as all the sown crowded on ?PPO~lteth~ ~s t~er pot died b~fore they grew self-fertilised. seedlings I~ ·ht IS t:e w~re not measured. The to any considerable heig ' y d hen between 7 and pl.a nths in· Pohtesi gI.h at nadn I dl. t hwe ercer omsseea dsue:;cee;ed the self-fertilised 8 Inc es In . ' . 7 inches When fully grown they were iang aaivne rmageea shumregdh tt ob yt h1e 5s ummi' ts. of thei'r flower-heads, with the following result:- TABLE XXXI. I Crossed Plants. J No. ofPot. S,·lf-fertilised Plants . of the Third Gene- I ration. Inches. Inches. I. 18 19 21 21 18a 19 ~ 1- - II. 19 16 a 18~ 7 ~ 11 H 14 ~ 21 ~ 16 ~ Total in inches. 133•88 114 •75 The average height of the seven crosse d p lants IS hero 19 ·12 CHAP. IV. CROSS WITH A FRESH STOCK. 105 inches, and that of the seven self-fertilised plants 16 · 39, or as 100 to 86. But as the plants on the self-fertilised side grow very unequally, this ratio cannot be fully trusted, and is probably too high. In both pots a crossed plant flowered before any one of the self-fertilised. These plants were loft uncovered in the greenhouse; but from being too much crowded they 'were not very productive. The seeds from all seven plants of both lots were counted; the crossed produced 206, and the self-fertilised 154; or as 100 to 75. · Cross by a fresh Stock.-From the doubts caused by the two first trials, in which it was not known with certainty that the plants had been crossed; and from the crossed plants in the last experiment having been put into competition with plants self-fertilised for three generations, which moreover grow very unequally, I resolved to repeat the trial on a larger scale, and in a rather different manner. I obtained seeds of the same crimson variety of I. umbellata from another nursery garden, and raised plants from them. Some of these plants were allowed to fertilise themselves spontaneously under a net; others were crossed by pollen taken from plants raised from seed sent me by Dr. Durando from Algiers, where the parent-plants had been cultivated for some generations. These latter plants differed in having pale pink instead of crimson flowers, but in no other respect. That the cross had been effective (though the flowers on tho crimson mother-plant had not been castrated) was well shown when the thirty crossed seedlings flowered, for twenty. four of them produced pale pink flowers, exactly like those of their father; the six others having crimson flowers exactly like those of their mother and like those of all the self-fertilised seedlings. This case offers a good instance of a result which not rarely follows from crossing varieties having differently coloured flowers; namely, that the colours do not blend, but resemble perfectly those either of the father or mother plant. The seeds of both lots, after germinating on sand, were planted on opposite sides of eight pots. When fully grown, the plants were measured to tthaeb lseu:m-mits of the flower-heads, as shown in the following |