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Show 228 ILLEGITIMATE OFFSPRING OF CnAP. V. these plants was greatly i1npaired. The lo~s is not correlated with the colour of the flower; and It was to ascertain this point that I made so many experiments. As the parent-plant growin? in Edinburgh .was. found by Mr. Scott to be i~ ~ high degree st~nle, It 1~ay have transmitted a sunllar tendency to Its offspnng, independently of their illegiti1nate. birth. I ar_n, h~\~ever, inclined to attribute some weight to the Illegitimacy of their descent, both from the analogy of other cases, and more especially from the fact that when the plants were legitimately fertilised with pollen of the common primrose they yielded an average, as Inay be seen in the table, of only :1 more seeds than when illegitimately fertilised with the sain~ l?ollen. ~ow ."'.e know that it is mninently charactenstic of the Illeg1t1- n1ate off.gpring of Prin~ula Siner~;sis that they yiolcl but few more seeds when legitimately fertilised than when fertilised with their own-form pollen. PRIMULA VERIS, Brit. Fl. Var. o.fficinalis of Linn., P. o.fficinalis of J acq. Seeds from the short-sty led form of the cowslip fertilised with pollen from the same for~ germi~ate so badly that I raised from three successiv~ sow1ngs only fourteen plants, which consisted _of nine shortstyled and five long-styled plants. H~~ce the shortstyled forn1 of the cowslip, when self-fertihsed, does not transmit the same form nearly so truly as does that of P. Sinensis. From the long-sty led form, ~l w~~s fertilised with its own-form pollen, I raised In t .e :first generation three long-styled plants,-fro~ theu seed 53 long-sty led grandchildren,-from tho.u seed 4 lon0'-styled great-grandchildren,-from then seed 6 20 long-styled great-great-grandchi· ld ren,-and la<- stly ' CHAP. V. HETEROSTYLED DIMORPHIC PLANTS. 229 from their seed 8 long-styled and 2 short-styled greatgreat- great-grandchildren. In this last generation short-styled plants appeared for the first time in the course of the six generations,-the parent long-styled plant which was fertilised with pollen froin another plant of the same form being counted as the first generation. Their appearance may be attributed to atavism. Fron1 two other long-styled plants, fertilised with their own-form pollen, 72 plants were raised, which consisted of 68 long-styled and 4 short-styled. So that altogether 162 plants were raised from illegitimately fertilised long-styled cowslips, and these consisted of 156 long-styled and 6 short-styled plants. We will now turn to the fertility and powers of growth possessed by the illegitimate plants. From a short-styled plant, fertilised with its own-forn1 pollen, one short-styled and two long-styled plants, and from a long-styled plant similarly fertilised three long-styled plants were at :first raised. The fertility of these six illegi ti1na te plants was carefully observed ; but I must pre1nise that I cannot give any satisf~1ctory standard of co1nparison as far as the nu1nber of the seeds is concerned; for though I counted the seeds of many legitimate plants fertilised legitim~toly and illegitimately, the number varied so greatly during successive seasons that no one standard will serve well for illegitimate unions made during different seasons. Moreover the seeds in the same capsule freq uen tl y differ so much in size that it is scarcely possible to decide which ought to be counted as good seed. There remains as the best standard of com paris on the proportional number of fertilised flowers which produce capsules containing any seed. First, for the one illegitimate short-styled plant. In the course of three seasons 27 flowers were illcgiti-, |
