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Show 168 SUMMARY ON THE LEGUMINOSJE. CHAP. v. . th ·. 1 0·ght being 164 supremacy, ou 1 1 and 15~·, whilst that of the · !; 4 . • 1 _ two soH-fertilised plants was 14~ .and 11s Inc les. . By the autumn of 1870, the hmghts wore as follows.- TABLE LXI. Onords mimtti.~sima. Cros,.;cd Plant.". S ·lf-fertili scct Plunt.:;. Inches. Inc b e::;. 20~ 17 ~ 19~ 17 2 39·63 34•75 So that tho mean height of the two cr?sRod plantR waR 1D · 81, and that of the two self-fertilised 17 · 37 1nchos ; or as 100 to 8~. It should be remembered that the two lots wore at first eq11al m height; that one of the self-fer~ilisf\d plant~ the~ l1ad the ad\'antage, the two crossed plants bomg at last v1ctonous. s~tmrnary on the Leguminosm.-Six genera in th.is fa1nily were experimented on, and tho results are In so1ne respects remarkable. The crossed plants o~ the two species of Lupinus w~re c~nspicnously ~upenor to the self-fertilised plants In ho1ght and fertility ; and ,vhen grown under very unfavoural>lo conditions, in vigour. The scarlet-runner (Phaseolus n~ultijlorus) is partially sterile if the visits of bee~ a~·o prevc.~ted, and there is reason to believe that vanetles growing ncar one another intercross. The five crossed plants, however exceeded in heirrht the five self-fertilised only by a' little. Phaseolus bv ulgaris is perfectly self-fert1'1 e; nevertheless, varieties growing in the same garden sometimes intercross largely. The varieties ofLathyr~ts odoratus, on the other hand, appear never to intercross in this country ; and though the flowers are not ofte? visited by ef-ficient insects, I cannot account for this fact, more especially as tho varieties are believed to CHAP. v. CLARKIA ELEGANS. 169 intereross in North Italy. Plants raised from a cross between two varieties, differing only in the colour of their flowers, grew much taller and were under unfavourable conditions more vigorous than the self-fertilised plants; they also transmitted, when self-fertilised their superiority to their offspring. The many varieties' of the con:m?n Pea ( Pisun~. sativum ), though growing in close proximity, very seldom intercross; and this seems due to the rarity in this country of the visits of bees sufficiently powerful to effect cross-fertilisation. A cross between the self-fertilised individuals of the same variety does no good whatever to the offspring; .. whilst a cross between distinct varieties, though closely allied, does great good, of which we have excellent evidence. The flowers of the Broom (Sarothamnus) are almost sterile if they are not disturbed and if insects are excluded. The pollen from a distinct plant is more effective than that from the same flower in producing seeds. The crossed seedlings have an enormous ad vantage over the self-fertilised when grown together in close competition. Lastly, only four plants of the Ononis 1ninutissima were raised; but as these were observed during their whole growth, the advantage of the crossed over the self-fertilised plants may, I think, be fully trusted. XV. ONAGRACEJ.EJ.-OLARKIA ELEGANS. Owing to the season being very unfavourable (1867), few of the flowers which I fertilised formed capsnles; twelve crossed fl?wers produced only four, and eighteen self-fertilised flowers Yielded only one capsule. Tho seeds after germinating on sand ~ere planted in three pots, but all the self-fertilised plants died In one of them. Whon the two lots were between 4 and 5 inches in height, the crossed began to show a slight superiority o~er the self-fertilised. When in full flower they were measured, With the following result :- |