OCR Text |
Show f)8 BRASSICA OLERACEA. CHAP. IV. 0RCC1FER1E, P A p A VERACElE, RE' SEDACElE, ETC. . . lants-Grcat effect of a . . crossed and self-fertih~ed p the offspring-Iberi::l lirl:lsstca ol?:~c:a,fresh stock on the wl mghhit:fa californica, seedlings cross Wl vagum _Esc 1sc 0 . us but more b llata-Papaver k ot more vigoro . , um e . . with a fresh stoc ~ n R da lutea and odorata, fron~ a mos:l self-fertilised seedh~gs- ese llcn-Viola tricolor, fertile ~hda~~id~als sterile with t~eu t?wlnis p~elphinium c.·onsolida many m Adoms res IVa f ·t'l than wonderfu~ effeci::: :~~~::a plants hardly taller, :~t:n~r:el~~f~r~ilised - Viscan~t~~~ed~Dianthus cary?phyllu~, c~o:~ects of a cross with the self-fei ed for four generatwns-GI ea n the self-fertilised plants compar '£ colour of the flowers o ·a fresh stock-Um ?:m p1a nt s-Hibiscus afncanus. CRUCIFER.lE.~ 13 RAS'S ICA OLERACEA. VI. . 0 ttell's Ea'rly Barnes Cavbaae. Va1. a d shown by mon cabbage are ada pte. ' as. . elf- THE flowers of the com. . . and should this fml, for s H Muller* for cross-ferbhsatwnt,h t the varietjes arc crossed so fe·r tilisatio'n . It I·S we 11 . k.n o.w n ssaib le to raise pure ln·n d s ·n the I . largely by insects, that >t lS >m~.o. d is in flower at the same tJ~e. same garden, if more than on~ I~t well fitted for my expenmen s, Cabbages, in one respect, wercd~ they were often djfficnlt to mea-. th had formed hea , ' h . ht. and a poOl as, after ey t lso differ much in mg ' f fine sure. The flower-s ems a h. her stem than that o a plant will sometjmes thr~w u~ at~~ fully-grown plant. were cut vlant. In the later expenmhen s, the immense advantage from a d weighed, and t en down an 'f t ·u a net cro1& ~~~:~~:~0~8 the above varier;;~~ ~~~~:dfr:~ ~nother ·ust before flowering, and was ~rossc~ose by. and the seven.cap· .ll~nt of the same variety growmg vera~e 16.3 seeds, wJth a p l thus produced contained on an a ~u cs · * , Die Befruchtung,' &c · p. 139. CHAP. IV. CROSSED AND SELF-FERTILISED PLANTS. 99 maximum of twenty in one capsule. Some flowers were artificially self-fertilised, but their capsules did not contain so many seeds as those from flowers spontaneously self-fertilised under the net, of which a considerable number wore produced. Fourteen of these latter capsules contained on an average 4·1 seeds, with a maximum in one of ten seeds; so that the seeds in the crossed capsules wer·c in number to those in the sclf-fm'tilised capsules as 100 to 25. Tho self-fertilised seeds, fifty-eight of which weighed 3 · 88 grains, were, however, a little finer than those from tho crossed capsules, fifty-eight of which weighed 3 · 76 grains. \iVhen few seeds are produced, these seem often to be better nourished and to be heavier than when many are produced. The two lots of seeds in an equal state of germination were planted, Rome on opposite sides of a single pot, and some in the open ground. Tho young crossed plants in the pot at first exceeded by a little in height the self-fertilised; then equalled them; were then beaten; and lastly were again victorious. The plants, without being disturbed, were turned out of the pot, and planted in the open ground; and after growing fm· Rome time, the crossed plants, which were all of nearly the same height, exceeded the self-fertilised ones by 2 inches. vVhen they flowered, the flower-stems of the tallest crossed plant exceeded that of the taUest self-fertilis0d plant by 6 inches. The other seedlings which were planted in the open ground stood separate, so that they did not compete with one another; nevertheless the crossed plants certainly grew to a rather greater height than the self-fertilised; but no measurements were made. The crossed plants which had been raised in the pot, and those planted in the open g1·ound, all flowered a little before the self-fertilised plants. Grossed and stlf-fertilised Plants qf the Second Generation.-Some flowers on the crossed plants of the last generation were again crossed with pollen from another crossed plant, and produced fine capsules. The flowers on the self-fertilised plants of the last generation were allowed to fertilise themselves spontaneously under a net, and they produced some remarkably fine capsules. The two lots of seeds thus produced germinated on sand, a;nd eight pairs wore planted on opposite sides of four pots. These plants were measured to the tips of their leaves on the 20th of October of the same year, and the eight crossed plants averaged in height 8 · 4 inches, whilst the self-fertilised averaged 8 ·53 inches, so that the crossed were a little inferior in height, as 100 to 101· 5. By the 5th of June of the following year these H 2 |