88 HYBRIDISING AND CROSS-BREEDING. 



to insect agency; for instance: i. Cultivation increases the 

 size and colour of flowers quite independently of the existence 

 or non-existence of insects. 2. Double flowers, in which the 

 doubling arises from metamorphosis of stamens or pistils, are 

 more showy than the single forms ; yet insects can be of little 

 use to them, since they are either partially or entirely barren. 

 The double-blossomed Cherry is brilliantly conspicuous, but 

 it bears no fruit. 3. Such abortive flowers as the cultivated 

 Guelder Rose and Hydrangea depend for their beauty upon 

 the destruction of the reproductive organs. If their increased 

 splendour is meant only as a lure to insects, it is surely an 

 absurd failure. 4. The autumn colours of leaves and fruits* 

 can serve no such purpose, yet these are often as bright and 

 conspicuous as the flowers of summer. 5. Fungi and Lichens 

 exhibit brilliant colours, which can have nothing to do with 

 insect fertilisation. Do not these facts indicate, that though 

 insects may be attracted by conspicuous colours, and may have 

 some influence in the maintenance of coloured species, there 

 is yet a deeper and more permanent cause for the colour 

 itself? 



Insects and Colour of Flowers. It is a curious fact that nearly 

 all night-blooming plants bear white flowers, and many species of 

 Cactaceous plants, especially Cereus, may be cited as examples, 

 together with long-spurred, nectar-laden Angraecums and 

 noble Yuccas ; while a further notable fact in connection with 

 night-flowering plants is, that their fragrance is scarcely per- 

 ceptible during bright daylight, and is almost overpowering 

 at night, especially in a hothouse or close room. Here the 

 colour and fragrance seem specially adapted to attract the 

 attention of nocturnal lepidoptera or other insects. The theory 

 that flowers owe their bright colours to insect agency is sup- 

 ported by the fact, that in the natural order of Orchids we 

 have the most lovely and varied of all floral beauty ; and this 

 order is singularly indebted to insects, without the assistance 

 of which, indeed, Orchid flowers cannot become fertilised in 

 their native habitats. Asclepiads in like manner are mainly 

 dependent on insect agency, just like Orchids; but in the first- 

 named group nectar would seem to be the principal attraction ; 

 while in the case of Orchids, colour and fragrance seem the 

 charms to lure the little "winged messengers of love." My 

 object here, however, is not to do what Darwin, Lubbock, 

 Huxley, and others have already done before me, but to show 



* The beauty of fruits, as shown by Prof. Hildebrand and Mr Darwin 

 (Origin of Species, chap, vi.), "serves merely as a guide to birds and 

 beasts, in order that the fruit may be devoured and the seeds disseminated. " 



