...destroyed. Besides, it does not often happen that the male and female organs of fructification, in different species, arrive at a state of maturity at precisely...wild upon a hill near Turin. Ranunculus lacerus, also steril, has been produced accidentally at Grenoble, and near Paris, by the union of two Kanunculi :...

...even if they were ever produced " See Barton on the Geography of Plants, p. 67. t Georg lib. iii. 273. beyond one generation in a wild state. In the universal...in which hybrids are acknowledged to be deficient. Cenlaurea hybrida, a plant which never bears seed, and is supposed to be produced by the frequent intermixture...

...generalized this 'war between the plants', arguing for a 'universal struggle for existence', in which 'the right of the strongest eventually prevails; and the strength and durability of the race depends mainly on its prolificness' — Every species which has spread itself from a small...

...Spencer), contains many references of this kind, including innumerable passages on struggle: for example, "In the universal struggle for existence, the right...in which hybrids are acknowledged to be deficient." Without working systematically I have seen fifteen other references to struggle in volume two alone....

...If, therefore, the relative fecundity or * Georg. lib. iii. 273. 56 RARITY OF HYBRIDS AMONG [Ch. IV. hardiness of hybrids be in the least degree inferior,...wild upon a hill near Turin. Ranunculus lacerus, also steril, has been produced accidentally at Grenoble, and near Paris, by the union of two Ranunculi ;...

...kingdom generally, it must be recollected, that even of the seeds which are well ripened, the greater part are either eaten by insects, birds, and other...plant which never bears seed, and is supposed to be pi-oduced by the frequent intermixture of two well-known species of Centaurea, grows wild upon a hill...

...had remarked on the phenomenon. There was, he said, a "universal strug• gle for existence" in which "the right of the strongest eventually prevails, and the strength and durability of the race (read species) depends mainly on its proliferations." By "proliferations," Lyell was referring...

...his correspondence especially between himself and Lyell * the Geologist who wrote to Darwin saying, 'In the universal struggle for existence, the right of the strongest eventually prevails'. (Quoted in Young on 'The Principles'. 1969). * In 1859 Darwin wrote to Lyell about the conditions of...

...growth.30 This awareness led him to comment on the "struggle for existence" in the following words : In the universal struggle for existence, the right...durability of a race depends mainly on its prolificness. . . .;il As Loren Eiseley has already shown, Darwin had encountered the idea of population pressure...