510 FERTILIZATION OF BRITISH ORCHIDS. [Dec. 



the stigma, and the plant therefore produces a seed without insect 

 aid. 023hrys a'pifera affords another example like the latter of self- 

 fertilization, for the anther cells naturally open and the masses of 

 pollen from their own weight fall down to the exact level of the 

 stigmatic surface, and are there made to vibrate by the slightest 

 breath of wind until the stigma is struck. It is curious that both 

 these species, although constantly self-fertilized, still retain various 

 structures which it is impossible to doubt are adapted for ensuring 

 cross-fertilization, though they are now rarely or never brought into 

 play. Orchis or Gymnadenia conopsea and the three species of the 

 genus Hahenaria have the viscid discs uncovered, but the pollinia 

 go through the same act of depression as in a true Orchis, and the 

 flowers are effectually fertilized by insects. 



Ccphalanthcrct grandijlora, although destitute of a rostellum, is 

 constantly self-fertilized while in the bud state by the emitting of a 

 multitude of tubes from the pollen grains. The structure and 

 manner of fertilization in Epipactis latifolia and E. pcdustris is both 

 complicated and beautiful. 



The usual movement of depression in the pollinia of these two 

 species does not take place, which may also be said of the genus 

 Spiranthcs and Goody era. Epipactis latifolia is, however, frequently 

 self-fertilized by the pollen falling spontaneously on the stigma. 

 It is also a curious fact in connection with this plant, that the 

 nectar should be so highly attractive to the red-tailed humble bee 

 that cannot fertilize the flower, while to the wasp that can remove 

 the pollen masses with ease, and thereby ensure cross-fertilization, 

 it offers but little attraction, as is clearly shown by the almost total 

 absence of its visits. (I have devoted a special paper to the 

 fertilization of this Ejnpactis in the forthcoming Transactions of the 

 Botanical Society of Edinburgh.) 



In Listcra ovata and L. cordata, the structure of whose 

 flowers is essentially the same, as also indeed is that of 

 Neottia Nidus-avis which has special adaptations for the ferti- 

 lization of the plants, the action of the reproductive organs is 

 both curious and instructive. As soon as the pollinia have become 

 attached to an insect's forehead, the rostellum suddenly curves 

 dovfnwards so as to project at right angles over the stigma, thus 

 protecting it from impregnation at an early age, and also to a greater 

 or less extent preventing self-fertilization. In the course of a day, 

 however, the rostellum not only recovers its original position, but 

 stands upright, leaving the stigmatic surface perfectly free for 

 pollen to be left on it by the first visiting insect. This is perhaps 

 the most remarkable, as regards structure and adaptation of one 

 part to another, of our native orchids, and also one that is 



