142 Flowers and their Unbidden Guests. 



external conditions are of advantage, and such varieties 

 may form a starting-point for new species. But that 

 which is of advantage to the attacking animal implies, as a 

 rule, a corresponding disadvantage to the plant attacked ; 

 and therefore not only is it possible, but in the course of 

 ages it has certainly happened innumerable times, that 

 in consequence of the development of some or other indi- 

 vidual advantageous variety of an animal into a species, 

 that is in consequence of the multiplication of this 

 advantageously organised fonn of animal within a 

 certain district, some plants in this same district have 

 been gradually exterminated, owing to the interference 

 on the part of their new enemies with the formation of 

 their flowers and seeds.^ 



I It must be borne in mind tbat there are species of plants which, 

 though they are provided with some or other of the appliances 

 described in this treatise, are nevertheless only im/perfedly protected 

 thereby from the attacks of those animals to which they are ex- 

 posed a< the present time. For instance, many of the nectariferous 

 flowers of our own flora, such as Aconitum, Pedicularis, Gentiana, 

 Khododendron, E.hinanthus, are liable to have their corolla gnawed 

 through, and their nectar rifled without profit to themselves (p. 125). 

 Some of these species, nevertheless, maintain themselves, and this 

 in abundance. The explanation of this is in the first place that 

 the flowers are not entirely unviaited by the proper opening, and 

 secondly, that, in default of allogamy by the agency of insects, the 

 flowering process terminates in autogamy (e.g. Ehododendron, Shin- 

 anthus). In several of these species, however, this is not the 

 case ; and these, as for instance Aconitum paniculatum Lam., are at 

 the present time rare ; they produce, moreover, as a mle, no seed, 

 are individually scarce, and may be fairly regarded as species on 

 the way to extinction. 



[It appears to me that the ordinary blue variety of j4cobj<im?i napellua 

 is protected from this lateral gnawing and useless expenditure of 

 nectar, at any rate to a great extent, by some or other distasteful 



