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Show 102 BRASSICA OLERACEA. CnAP. IV. Early in the spring the plants were gradually hardened, and turned out of their pots into the open ground without being disturbed. By the end of August the greater number had formed fine heads, but several grew extremely crooked, from having been drawn up to the light whilst in the greenhouse. As it was scarcely possible to measure their heights, the finest plant on each side of each pot was cut down close to the ground and weighed. In the preceding table we have the result. Tbe six finest crossed plants average 108 ·16 ounces, whilst the six finest self-fertilised plants average only 23 · 7 ounces, or as 100 to 22. This difference shows in the clearest manner the enormous benefit which these plants derived from a cross with another plant belonging to the same sub-variety, but to a fresh stock, and grown during at least the three previous generations under somewhat different conditions. The O.tfspring from a cut-leaved, curled, and variegated white-green Oabbage crossed uith a cut-leaved, curled, and var1'egated c1·imson-green Cabbage, compared with the self-fertil?:.•ed O.tfspriny from the two Varieties.-These trials were made, not for the sake of comparing the growth of the crossed and self-fertilised seedlings, but because I had seen it stated that these varieties would not naturally intercross when growing uncovered and near one another. This statement proved quite erroneous; but the white-green variety was in some degree sterile in my garden, producing little pollen and few seeds. It was therefore no wonder that seedlings raised from the self-fertilised flowers of this variety were greatly exceeded in height by seedlings from ::t cross between it and the more vigorous crimson-green variety; and nothing more need be said about this experiment.. The seedlings from the reciprocal cross, that is, from the crimson- green variety fertilised with pollen from the white-green variety, offer a somewhat more curious cage. A. few of these crossed seedlings reverted to a pure green variety with their leaves less cut and curled, so that they were altogether in a much more natural state, and these plants grew more vigorously and taller than any of the others. Now it is a strange fact that a much larger number of the self-fertilised seedlings from the crimson-green variety than of the crossed seedlings thu's reverted; and as a consequence the self-fertilised seedlings grew taller by 2~ inches on an average than the crossed seedlings, with which they were put into competition. A.t first, however, the crossed seedlings exceeded the self-fertilised by an aveTage of a quarter CHAP. IV. IBERIS UMBELLATA f . . 10:1 0. ~n Inch. vVe thus see that l'CVCrsion ditiOn acted more powerfully . f: , . to a more natural con-of these plants than di'd In avounng the ultimate arowtll th a cross· but 't ·h ld 0 at the cross was with a . ' . I s ou be remembered constitution. ' semi-stenle variety having a feeble IBERIS UMBELLATA. Var. Kermesiana. This variety produced lent seed under a net. Other pplanfs ~~ spont.aneously self-fertilised left uncovered, and as I saw small ~~ts.Jn. t.h~ greenhouse were seemed probable that they would be i es VIsiting the flowers, it seeds supposed to have been th ntercrossed. Consequently fertilised seeds were so us crossed and spontaneously self self-fertilised seedlings wn onf opposite sides of a pot Tb~ grew rom the first . k . supposed crossed seedlings and h quiC er than the flower the former were from 5 t 6 . when ~oth lots were in full I d · · 0 recor Ill my notes that the Inc es .h .1 gher tha n the crossed! these self-fertilised pia . se~f-fertihsed seeds from which th n r;il were l'aJsed we t a~ e crossed; and this rna . reno so well ripened difference in their oTowth . y possibly have caused the oTeat a o ' In a somewhat I o s occurred with the self-fertilised 1 an~ ogous manner o~ Ipomcea raised from unhealtK ants of the eJgh~h generation Circu~stance, that two other lot: ~a~ents. It Is a curious sown In pure sand mixed with b t he above seeds were out any organic matte . durnh earth, and therefore with-dl' r ' an ere the see Ings grew to double the height f th supp~s~d crossed bohth lots died, as necessarily occurre~ t e self-fertilised, before s all hereafter meet with th a an early period. We to th.IS of Iberis in the th · d ano er . case 'a ppa ren tlY analogous The above self-fertilise~r a:e~eratwn of Petunia. selves again under a net r i~d~:~re allow~~ to fertilise themsecond generation and th' Y g self-fertilised plants of the by II ' e supposed crossed pi t . po en of a distinct plant. but f ~n s were crossed m a careless manner namel~ b rom ':ant of time this was done flowers over anothe;. I sho~l~ ~mean~g one head of expanded have succeeded and perha s 't a:e t ought that this would of the self-fcrtili~ed seeds wef.h .1 ~~ so; ~ut the fact of 108 number of the supposed cross~ding .87 ?rains, whilst the same does not look like it F' dl~eeds wmghed only 3. 57 grains ra· d . Ive see Jngs from ea h 1 t f ' Ise ' and the self-fertilised 1 G c o o seed~? were p ants, when fully grown, exceeded |