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Show 290 CONSTITUTIONAL VIGOUR CnAP. VIII. scopari'~ts were not touched Ly a very severo winter . whereas all the self-fertilised plants wore killed half~ way down to the ground, so that they wore not able to flower during tho next snm1ner. Young crossed seedlings of Nicotiana withstood a cold and wet sum1ner much better than the self-fertilised seedlings. I have met with only one exception to tho rnle of crossed P,lants being hardier than the self-fertilised : three long rows of Eschscholtzia plants, con jsting of erossod seedlings from a fro h stock, of intercrossed seedlings of the same stock, and of self-fertilised ones were left unprotected during a severo winter, and all' perished except two of the self-fertilised. But this · case is not so anomalous as it at :first appears, for it should be remembered that the self-fertili eel plants of Eschscholtzia always grow taller an<l arc heavier than the crossed; the whole benefit of a cross with this species being confined to increas c1 fertility. Independently of any extern<-tl cause which could be detected, the s If-fertilised plants were more liable to premature death than were tho crossed· and this seems to me a c_urious fact. vVhilst tho ' seedlings were very young, if one died its antagonist was pulled up and thrown away, and I believe th~.t many more of tho self-fertilised died at this early age than of the crossed ; but I neglected to keep any record. vVith Beta vulgaris, howov r, it is certain that a large number of the self-fertilised so ds perished after gonuina6ng beneath the ground, w her as the crossed seeds sown at the san1e time did not thus suffer. When a plant died at a somewhat more advanced ao·o the fttet was b reeordocl; and I find in my notes that out of several huudrecl plants, only seven of the crossed died, whilst of the self-fertilised at . least two11ty-nine were thus lost, that is more than four tin1cs as mt~ny. Mr. Galton, CHAP. VIII. OF THE CROSSED PLANTS. 291 after examining some of my tables, rmnarks: " It is very evident that the columns with the self-fertilised plants include the larger number of exceptionally s1nall plants;" and the frequent presence of such puny plants no doubt stands in close relation with their liability to premature death. The self-fertilised plants of Petunia completed their growth and bega~ to wither sooner than did the intercrossecl plants; and these latter considerably before the offspring fro1n a cross with a fresh stock. Period of Flowering.-ln some caHes, as with Digitalis, Dianthus, and Reseda, a larger number of the crossed than of the self-fertilised plants threw up flower-stems ; but this probably was merely the result of their greater power of growth ; for in the first generation of Lobelia fulgens, in which the self-fertilised plants greatly exceeded in height the crossed plants, some of the latter failed to throw up flower-stems. With a large n urn ber of species, the crossed plants exhibited a well-marked tendency to flower before the self-fertilised ones growing in the same pots. It should howev r be remarked that no record was kept of the flowering of many of the species; and when a record was kept, the flowering of the first plant in each pot was alone observed, although two or more pairs grew in the sa1no pot. I will now give three lists,-one of tho species in which the first plant that flowered was a cross d one,-a second in which the first that. flowered was n self-fertilised plant,-ancl a third of those whi h flowered at the same time. Species, of which the first Plants that flowered u:ere of Grossed Parentage. Ipornrea purpurea.-I record in my notes that in all ten generations many of the cro sed plants flowered before the selffertilised; but no details were kept. u 2 |