cox, DARWIN AND THE MUTATION THEORY 439 



in that of the Imantophyllum, &c., there is no known natural species or variety from 

 which the characters in question could have been derived by a cross. We must 

 attribute all such cases to the appearance of absolutely new characters in the buds. 

 The varieties which have thus arisen can not be distinguished by any external char- 

 acter from seedlings .... It deserves notice that all the plants which have yielded bud- 

 variations have likewise varied greatly by seed." ' 



Now, Darwin is here treating of saltations among cultivated plants, 

 but it is instructive to read in this connection the following passage in which 

 he prepares the ground for a belief in the possibility of similar abrupt and 

 wide variations under natural conditions. He remarks: 



" Domesticated animals and plants can hardly have been exposed to greater 

 changes in their conditions of life than have many natural species during the inces- 

 sant geological, geographical, and climatal changes to which the world has been 

 subject; but domesticated productions will often have been exposed to more sudden 

 changes and to less continuously uniform conditions. As man has domesticated so 

 many animals and plants belonging to widely different classes, and as he certainly 

 did not choose with prophetic instinct those species which would vary most, we may 

 infer that all natural species, if exposed to analogous conditions, would, on an 

 average, vary to the same degree." - 



But now let us take a specific example of spontaneous variability which 

 deeply impressed Mr. Darwin. It is a case which was brought to his atten- 

 tion in 1860 by Professor W. H. Harvey concerning Begonia frigida, as to 

 which Mr. Darwin says: 



"This plant properly produces male and female flowers on the same fascicle; and 

 in the female flowers the perianth is superior; but a plant at Kew produced, besides 

 the ordinary flowers, others which graduated towards a perfect hermaphrodite 

 structure; and in these flowers the perianth was inferior. To show the importance 

 of this modification under a classificatory point of view, I may quote what Professor 

 Harvey says, namely, that had it ' occurred in a state of nature, and had a botanist 

 collected a plant with such flowers, he would not only have placed it in a distinct 

 genus from Begonia, but would probablj^ have considered it as the type of a new 

 natural order.' . . . .The interest of the case is largely added to by Mr. C. W. Crocker's 

 observation that seedlings from the normal flowers produced plants which bore, in 

 about the same proportion as the parent-plant, hermaphrodite flowers having infe- 

 rior perianths." ^ 



This was written in the first edition of "Animals and Plants Under 

 Domestication" (1868) and was allowed to stand in the second and last 

 edition (1875). In both editions, however, Mr. Darwin made the state- 

 ment in an entirely different part of the work, that "the wonderfully anoma- 



1 " Animals and Plants Under Domestication," 2d ed., Vol. I, pp. 439-40. 



See also ibid., Vol. II, p. 278. 



2 Ibid., Vol. II, p. 401-2. 



3 Ibid., Vol. I, p. 389. 



