1885.] FEETILIZATION OF BRITISH ORCHIDS. 511 



readily examined by any person wishing to observe the method of 

 fertilization, 



Malaxis paludosa, with its upturned labellum, is freely fertilized 

 by insects to which the flowers are highly attractive. The genus 

 Cypripedium, of which we have but one British representative (6'. 

 calceohis), differs in a remarkable degree from any of those already 

 described. In most British orchids, the stigma is viscid and more 

 or less concave, and the grains of pollen united together in dry 

 masses ; whereas in Cypripedium the reverse of this is the case, the 

 stigma being slightly convex and non-viscid, and the pollen grains 

 coated by and immersed in viscid fluid. The labellum forms a large 

 inflated pouch, the basal part of which is folded round the column 

 so that its edges nearly meet along the dorsal surface, while the 

 extremity is folded over, thus forming a sort of shoe, which suggested 

 not only the English name of the genus — Lady's slipper — ^but also 

 the Latin Cypripedium or Venus's slipper. The opening into the 

 slipper from being partly closed by the stigma has a horse-shoe like 

 form, and, owing to the edges of the labellum being much inflected, 

 insects which have once entered the flower experience no little 

 difficulty in escaping by the same way, but, unless in the case of 

 very large insects, are compelled to crawl out by one of the two 

 small orifices close] to the anthers. In doing this, they inevitably 

 come in contact with and carry off some of the glutinous pollen. 



I have repeatedly caught small bees and placed them within the 

 labellum of Cypripedium calceohis growing in my own garden, and 

 thus clearly saw the whole method of fertilization. The bee, after 

 repeated attempts to get out by the way it entered, which it could 

 not owing to the edges of the labellum being inflected, at last forced 

 its way out through one of the small openings close to the anthers. 

 The inner surface of the labellum is, I have also noticed, covered 

 with minute hairs which, from being recurved or inclined downwards 

 from the large opening in the labellum, also prevent the insect that 

 has once entered from escaping by the same orifice. Having had 

 at various times most of the orchids just treated of under cultiva- 

 tion, ample opportunities were afforded me during leisure hours of 

 investigating, by the help of Darwin's valuable work on that subject, 

 their peculiar structure and methods of fertilization, an occupation 

 which I must say has afforded me no small amount of pleasure as 

 well as instruction. 



