CORRESPONDENCE. 



The Natural History of the Flower. 



Mr. J. C. Willis (Natural Science, vol. iv., p. 347), I am glad to see, has 

 arrived at precisely the same result in his experimental study of flowers as I 

 maintained six years ago in my book, "The Origin of Floral Structures," etc., 

 viz., that the phenomena bearing on sex, cleistogamy,etc., "are primarily due to the 

 action upon the plant of external causes." The only point to which I cannot 

 follow him is when he says, " Natural Selection apparently only begins to act 

 later on." I would ask what facts are producible to prove that Natural Selection 

 acts at all on the maintenance, if not the origin, of any floral and, indeed, other 

 structures ? Be it observed that his first conclusion, just stated, is based on 

 positive facts which are accumulative ; the second, that Natural Selection plays 

 a part, is an assumption for which he supplies none. 



Mr. Willis is by no means alone in thus introducing Natural Selection. For 

 example, Mr. Cockerell, in describing the dwarf character of many high Alpine 

 plants, which he attributes to the direct action of the environment, adds: "It 

 appears, however, that Natural Selection may come into play," etc., and gives 

 three hypothetical applications [Nature, xliii., 1891, p. 207). It seems to me these 

 and other similar appeals to Natural Selection are simply a sort of unconscious 

 tribute to Mr. Darwin ; but since the adaptations as described by these authors are 

 all illustrations of plants varying in definite directions in response to the 

 environment, surely it would be a higher tribute to him to quote his 

 own description not only of such an origin of variation, but of its maintenance. 

 For not only does he say that "Natural Selection has no relation whatever 

 to the primary cause of any modification of structure" (Anivi. and PI. under 

 Dom., ii., p. 272); but he observes: "By the term definite action I mean 

 an action of such a nature that when many individuals of the same variety 

 are exposed during several generations to any change in their physical conditions 

 of life, all, or nearly all, the individuals are modified in the same manner. A new 

 subvariety would thus be produced without the aid of Natural Selection." [Anim. and 

 PL. etc., ii., p. 271). 



Mr. Darwin, arguing from cultivated plants — in which indefinite variation is 

 the rule, so that artificial selection is absolutely necessary — imagined indefinite 

 variation to be also the rule in Nature, and definite variation to be the exception. 

 Such is, however, not the case. Variation in Nature is always, as Mr. Willis, Mr. 

 Cockerell, and many other writers have of late years maintained, in strict adaptation 

 to the direct action of the environment ; in other words, natural variation is ahvays 

 definite. Hence Mr. Darwin himself proves, though contrary to the title of his 

 book, that the origin and maintenance of specific characters are without the aid 

 of Natural Selection. 



George Henslow. 



Sir, — From the fact that our flora resembles the flora of northern Europe in 

 being visited by a larger proportion of flies than has been observed in the neighbouring 

 regions of the Continent, Mr. J. C. Willis infers that "our flora would seem rather 

 more closely allied to these northern floras in this respect than to the nearer Con- 

 tinental flora" (Natural Science, iv., p. 349). Before this inference can be 

 accepted it will be necessary to prove that this resemblance is not merely the result 

 of similar circumstances, such as the natural preponderance of flies over other 

 insects in our own and northern countries 



