isi BOTANICAL GAZETTE. 



ty having taken its place. But Mr. Henslow, reading this the other 

 way, having determined ''that self-fertilization i^^per se a decided ad- 

 vantage," and free from injurious liability, comes to regard inter- 

 crossing as merely ''a compensatory process for the loss of self-fertil- 

 ity.'^ 



But how and why did this "compensatory process come to pass ? 

 It is conceived on both sides that llowers were "primordially incon- 

 spicuous." (To this Henslow adds hermaphrodite and self-fertile; 

 but that need not liere come into account.) Both agree that insects 

 liave mainly determined their conspicuousness. Darwin says this has 

 been determined through natural selection by the survival of the 

 more and more conspicuous variations, correlated with their produc- 

 ing something good for the insect of which the coloration was a sign, 

 and that the preferential survival of the more showy and attractive 

 was a consequence of some benefit of the intercrossing. Henslow 

 propounds the view that insects have determined the conspicuousness 

 more directly, and not by benefiting but by irritating the flowers. 

 "These, by being greatly stimulated by the repeated visits of insects, 

 tend to become hypertrophied. Hence the corolla enlarges, becomes 

 more briglitly colored, the nectariferous organs increase the quantity 

 of secretion, and the stamens develope more pollen. Such being the 

 case, nourishment is withheld from the pistil, which is delayed in its 

 development; consequently such a flower is very generally proterand- 

 rous." Mr. Darwin might accept t!iis as an ingenious conception of 

 the way the specialization comes about, still insisting on the advan- 

 tage of the resulting intercrossing — -'or else the thing would hardly 

 come to pass," as the poet has it. And Mr. Heiislow's hypothesis has 

 to be supplemented to account for proterogyny, which is not much 

 less common. But Henslow's supposed process works evil instead of 

 good, and is therefore utterly anti-Darwinian and ''dysteleological." 

 For the result is a disturbance of tiie equilibrium and proper correla- 

 tion between the androecium and gynoecium ; and this, carried furth- 

 er,' should upon this view result in the monoecious and dioecious 

 states. So, accordingly, the cross-fertilization which comes into play 

 in the case of separated sexes, and in that of self-sterile hermaphrod 

 itism, is not for any good there is in it per .sv, but because it may no 

 better be. And all the elaborate, exquisite, and w^onderfully various 

 modes of adaptation of flowers to insects are only ways of repairing 

 the damages inthcted upon blossoms by insects through their persist- 

 ent visits I Did Mr. Henslow ever ask himself the question why the 

 sexes are separate in animals^ 



