CYPRIPEDIUM. 3 



visibly yielding ground to the pressure of cultivation and the presence 

 of a dense population ; and this is also true of all the Japanese and 

 of several of the North American species. 



The true cause of the gradual extinction of the race is probably to be 

 sought for in the reproductive organs of the flowers. A very cursory 

 examination of these must satisfy most observers that self-fertilisation 

 is impossible,* and the sexual apparatus is so constructed that 

 few among existing races of insects are found capable of effecting the 

 necessary act of fertilisation that secures the perpetuation of the plant 

 by seeds, f Dr. Hermann Miiller, one of the most patient and accurate 

 observers of the fertilisation of flowers by insect agency, has enumerated 

 but five species of Andrena (Bees) that he detected fertilising the flowers of 

 Cypripedium Calceolus, and which, " attracted by the perfume of the flowers, 

 fly into the slipper-shaped lip, and lick and bite the hairs lining its floor, 

 which are sometimes covered with small drops of honey. "J Now the flowers 

 of tropical Cypripedes are absolutely devoid of perfume, and although the 

 inner surface of their labellum is studded with short bristly hairs, as in 

 G. Galceolus, we have never, after repeated trials, been able to detect any 

 secretion from them or from any other part of the pouch that possesses 

 any trace of sweetness to the taste, like the honey exuded from the 

 base of the column and ovary of other tropical orchids, as Cattleya, 

 Dendrobium, Odontoglossum, etc. ; hence we are tempted to believe that 

 the tropical Cypripedes, like some of our native orchids, must be reckoned 

 among C. C. Sprengel's category of Schemsaftblumen (Sham-nectar- 

 producers). The labellum, in fact, acts rather like a trap than a bait, 

 for when insects of any size, as bees, that have entered by the aperture 

 in front of the staminode endeavour to make their exit through the 

 lateral openings, they are liable to be held fast by the sticky pollen till 

 they perish miserably; indeed, Miiller observed that even "smaller bees 

 and flies that are too large to pass freely through the lateral orifices and 

 too Weak to force their sides apart, must, as a rule, perish of hunger 

 within the labellum." That the tropical Cypripedes are similarly circum- 

 stanced in their relation to insect visits is in the highest degree probable, for 

 direct observations are, unfortunately, altogether wanting ; and the probability 

 is strengthened by the fact that among the thousands of plants imported 

 by us during the past thirty years, we have rarely noticed a single seed 



* Cypripedium Schlimii is an exception. The flowers of this species are self-fertilising, 

 which often results in the maturing of seed capsules, with the effect, however, of producing 

 a progeny so enfeebled in constitution, that it is one of the most difficult of Cypripedes to import 

 alive and to get established in the glass houses of Ejpope. Its excessive fertility is its own 

 destruction. 



+ See illustration, page 7. 



+ Fertilisation of Floivers, translated by D. W. Thompson, p. 539. For the manner in which 

 the fertilisation of Cypripedium would be effected through the intervention of bees or other 

 insects, the reader is referred to the place here quoted, and to Darwin's Fertilisation of Orchids. 

 p. 270, 



