THE FERTILISATION OF FLOWERS. 337 



240 a), each adherent to a disc (Fig. 22 j , //), which in turn lies within 

 the rostellum or cup (r~). When touched, the rostellum breaks 

 across, and thus allows the two glutinous discs (12, d} to become 

 exposed. When a bee visits this peculiar flower, it pushes its pro- 

 boscis into the nectary () for the sake of the honey contained 

 therein. At the same time, the insect comes in contact with the discs 

 of the pollen-masses (Fig. 239), these masses becoming adherent to 

 the insect's head. A pencil pushed into an orchis detaches the 

 pollen-masses after the fashion of the insect's unconscious act. 

 At first, the pollen-masses remain erect like two abnormal horns 

 on the insect's head ; but gradually they assume a horizontal position, 

 so that the insect cannot fail to charge the next orchid-pistil it 

 enters with the pollen-masses. The stigma, or top of the pistil 

 (Fig. 238, st, sf), is so placed in these flowers that pollen-masses 

 borne on a bee's head are certain to strike this surface, and thus 

 fertilise the contents of the ovary. It is probable that as each 

 pollen-mass consists of several packets of pollen-grains, one mass 

 may contain material enough to fertilise several flowers ; each stigma, 

 through its viscid surface, detaching sufficient pollen from the mass 

 for its fertilisation. The admirable adaptation of flower to insect 

 and insect to flower, thus witnessed, is in no detail better exem- 

 plified than in the fact that the pollen-mass at first retains a vertical 

 and then assumes a horizontal position in the insect's head. So long 

 as the pollen- mass is vertical, fertilisation is impossible; and hence 

 the vertical position persists so long as the bee is engaged in 

 visiting the flowers of the plant from which it has derived pollen- 

 masses. Thus self-fertilisation is prevented ; so that, as Sir Joseph 

 Hooker puts it, by the time the horizontal position of the pollen- 

 mass is assumed, " the bee has visited all the flowers of the plant 

 from which it took the pollen, and has gone to another plant." 



To enter into further illustration of the contrivances through 

 which the fertilisation of flowers is secured would be to encroach 

 on the province of the technical and practical botanist. Such 

 details are " writ large " in the pages of every botanical text-book. 

 In the works of Mr. Darwin and especially in the " Fertilisation 

 of Orchids" the reader anxious for further details may find a 

 perfect encyclopaedia of facts constituting a veritable romance of 

 botanical science. It, however, remains to us in the present instance 

 to point out the plain meaning of these virtually marvellous adapta~ 

 tions of the plant-world to the work of cross-fertilisation, and to 

 note, as far as possible, the bearing of such a study upon the order 

 of nature regarded as a harmonious whole. It is a perfectly legitimate 

 supposition that if cross-fertilisation forms, as we have seen, such a 

 prominent feature of plant-life, that life must, in some very plain and 

 obvious fashion, benefit therefrom. And further, as plant-life is but 



z 



