Page:On the Various Contrivances by Which British and Foreign Orchids are Fertilised by Insects, and on the Good Effects of Intercrossing.djvu/13

 insects. Listera is generally fertilised by small Hymenoptera; Spiranthes by humble-bees. Mr. Marshall found that fifteen plants of Ophrys muscifera, transplanted to Ely, had not one pollen-mass removed; so it was during the first summer with Epipactis latifolia planted in my own garden; during the following summer six flowers out of ten had their pollinia removed by some insect. These facts possibly indicate that certain Orchids require special insects for their fertilisation. On the other hand, Malaxis paludosa, placed in a bog about two miles from that in which it grew, had most of its pollinia immediately removed.

The list which follows serves to show that in most cases moths perform the work of fertilisation effectually. But the list by no means gives a fair idea how effectually it is done; for I have often found nearly all the pollinia removed; but generally I kept an exact record in exceptional cases only, as may be seen by the appended remarks. Moreover, in most cases, the pollinia which had not been removed were in the upper flowers beneath the buds, and many of these would probably have been subsequently removed. I have often found abundance of pollen on the stigmas of flowers which had not their own pollinia removed, showing that they had been visited by insects; in many other flowers the pollinia had been removed, but no pollen had, as yet, been left on their stigmas.

In the second lot of O. morio, given in the list, we see the injurious effects of the extraordinary cold and wet season of 1860 in the infrequency of the visits of insects, and, consequently, on the fertilisation of this Orchid. Very few seed-capsules were produced this year.

In O. pyramidalis I have examined spikes in which every single expanded flower had its pollinia removed. The forty-nine lower flowers of a spike from Folkestone (sent me by Sir Charles Lyell) actually produced forty-eigtheight [sic] fine seed-capsules; and of the sixty-nine flowers in three other spikes, seven alone had failed to produce capsules. These facts show conclusively how well moths had performed their office of marriage- priests.

In the list, the third lot of O. pyramidalis grew on a steep grassy bank, overhanging the sea near Torquay, and where there were no bushes or other shelter for moths; being surprised how few pollinia had been removed, though the spikes were old, and very many of the lower flowers had withered, I gathered, for comparison, six other spikes from two bushy and sheltered valleys, half a mile on each side of the exposed bank; these spikes were certainly younger, and would probably have had several more of their pollinia removed; but in their present condition we see how much more frequently they had been visited by moths, and consequently fertilised, than those growing on the much exposed bank. The Bee Ophrys and O. pyramidalis, in many parts of England, grow mingled together; and they did so here, but the Bee Ophrys, instead of being, as usual, the rarer species, was here much more abundant than O. pyramidalis; no one would readily have suspected that probably one chief reason of this difference was, that the exposed situation was unfavourable to moths, and