210 THE ORIGIN OF SPECIES [pt. ii 



reality of little or no value to the organism concerned. It will 

 suffice to recall to memory the controversies about Drosera and 

 its insectivorous habits, the work of Kamerling upon xerophily, 

 or the characters of the Podostemaceae and Tristichaceae (124), 

 which are extremely striking and varied, though there are no 

 differences in conditions to which to be adapted. Stomata with 

 an outer pit entrance undoubtedly diminish transpiration, and 

 were once considered an adaptation to that end, but one finds 

 them on the inner wall of the fruit in the opium poppy, where 

 transpiration cannot matter (112). Ant-plants were supposed 

 to gain from their association with ants, but one may see the 

 Cecropia flourishing without ants all over the forests of Southern 

 Brazil, and the ants bring aphides, which must do much harm 

 to the plants. Epiphytes were supposed to be a particular 

 adaptation, till Schimper showed that plants became epiphytic 

 when they had three properties in common — easily dispersed 

 seeds, clasping roots, and capacity to resist drought for long 

 periods. And so on; the old adaptation explanation has been 

 shown to be of service in many fewer cases than had been 

 supposed the case. 



There can be no doubt that the idea of adaptation was pushed 

 to extremes, and that adaptations were found in many features 

 that have since proved to be almost or quite indifferent. Went 

 (112, p. 260) has treated this subject so fully that there is no 

 need to repeat his criticisms, and he has also ])ointed out that 

 when real adaptation exists, it is chiefly in plants that live under 

 extreme conditions, and that it is rare in mesophytic types, to 

 which probably the bulk of plants belong. It is quite possible 

 that it is in this way that one may explain the fact that in the 

 Bahamas the local endemics are almost as widely distributed as 

 the "wides" (p. 64), 



Another great difficulty for natural selection is that in many 

 cases the distinguishing characters do not appear (119) until the 

 struggle for existence is long over, for there is no doubt that the 

 vast proportion of the mortality is among the young seedlings. 

 What possible difference can it make to a plant that does not 

 flower till it is thirty years old, to take a single instance, whether 

 its calyx is smooth or ribbed? 



The' fact that allied species usually live near together is a 

 strong general argument against the idea that advantage has 

 anything to do (in any important measure) with the origin of 

 most species. Another is that for selection to produce any great 



