238 The Irish Naturalist. November, 



l)een not merely useless and purposeless but harmful ? They have, no 

 doubt, turned out harmfully in certain cases. Over-adapted plants, like 

 Inunan beings that "put all their eggs in one basket," have sometimes 

 incurred the failure ■which they courted by speculating too fiercely. 

 Others, more fortunate, may have saved themselves in the nick of time, 

 by reverting, as the Bee Orchis seems to have done, to self-fertilisation 

 when its insect friends, for some reason or other, failed it. But such 

 cases would be poor evidence to adduce as proof that the plant-world as 

 a whole made a huge mistake when it set out on the road to cross- 

 fertilisation. 



Messrs. Dewar and P'inn rely on what may be a parallel to the case 

 of the Bee Orchis — that of the genus Viola — as evidence that the aban- 

 donment of cross-fertilisation should be regarded as a progressive, not 

 retrogressive development. For this "advanced genus" has taken to 

 self- fertilisation through its cleistogamous flowers, which never open, and 

 so cannot be visited by insects, while, " according to Bentham,the Pansy 

 ( Viola tricolor) is the only British species of Viola in which the showy 

 flowers produce seeds." Attentive readers of this journal will take the 

 statement just quoted as to the British members of the genus Viola with 

 some reserve ; for Mr. G. C. Druce has in a recent number'' brought for- 

 ward additional evidence to that already existing^ for the well-attested 

 fact that Viola stagnina in different parts of its West of Ireland range 

 h^■bridises pretty freely with its ally V. canina. The production of 

 hybrids manifestly implies cross-fertilisation and insect-agency in the 

 case of both the parent species. But even if the facts were more in 

 accordance with the authors' argument, the argument itself w-ould be a 

 self-destructive one. The fact of one "advanced genus" having fallen 

 back on self-fertilisation would clearly be a much less powerful argument 

 for the superior usefulness of that process than the similar argument 

 furnished to the contrary by the many hundreds of advanced genera in 

 which the once general rule of self-fertilisation has been discarded. 



We cannot at all agree with our authors that "a weighty objection to 

 the theory that the colours of flowers have been developed because they 

 attract insects has been urged by Mr. E. Kay Robinson, namely, that 

 among wild flowers the most highly coloured are the least attractive to 

 insects." It is true enough that insects go in swarms to many incon- 

 spicuous flowers like those of the ivy, spurge-laurel, and bramble, while 

 the showy poppies, irises, and dog-roses attract much smaller numbervS. 

 But surely this, instead of a "weighty objection," is precisely what 

 might be expected. The plants that are attractive to only a few insects 

 are just those that vshould need a conspicuous standard to be seen from 

 afar, while to those that are eagerly sought by myriads flaming advertise- 

 ments are unnecessary. 



The attack on warning colours is, we think, vitiated by oversights 

 similar to that implied in the passage last criticised. Our authors 

 suggest, for example, that warning colour is not likely to be needed by 



^ Irish Naturalist, October, 1909, p. 209. 



''■ Praeger, '-Tourist's Flora of the West of Ireland," p. 123. 



