Fox: SPECIES OF CYPRIPEDIUM. 427 



The question as to the insects being instrumental in the pol- 

 lination of this genus seems yet to be an open one by reason of 

 the noted observation of Darwin and H. MiiUer. The latter 

 studied Cypripedium calceolus L. American forms closely 

 related to this, Cypripedium hirsutum Mill, and Cypripedium 

 acaule Ait. were studied by Darwin and Gray. 



Of the insects observed by Mailer, five species of bees were 

 found to frequent the flowers of C. calceolus L. and aid in pol- 

 lination. He writes that Andrewa fulvicrus K., A. albicans R., 

 A. atriceps R. , and A. pratensis, 2 with others were attracted 

 by the flower and flew into the lip through the orifice, landing 

 upon the hairs lining the floor of the labellum. Then they 

 sought to escape by climbing up the sides, and finally ended by 

 creeping beneath the stigma and escaping through one of the 

 two small lateral openings at the base of the lip. By this act- 

 ion one shoulder of the bee was smeared with the sticky pollen 

 from the anther above. When the bee visits another flower, it 

 again creeps under the stigma and is relieved of some of the 

 pollen by the papillae borne on the stigma. Other methods 

 of pollination are quite probable for other species, and Mailer 

 quotes Delpino as believing that Cypripedium caudatum Lindl. 

 is pollinated by the aid of snails, ^i That pollination is effected 

 solely by insects is doubted and although Orchids seem to be 

 adapted only for cross-pollination, yet the suggestion is made by 

 Morong that some may be capable of close-pollination. 22 This 

 has been deemed worthy of serious consideration in spite of 

 the fact that Darwin found that some Orchids when pollinated 

 with their own pollen seemed to be poisoned rather than bene- 

 fitted."^ 3 Ttie same thing is quoted from F. Muller by Sir John 

 Lubbock. 2 4 



Two factors seem to offer an explanation for the comparative 

 rarity of Orchids, first, their dependence upon external aid, 

 and second, the period of time elapsing between pollination 

 and fecundation. 2 5 Indeed, some instances have been found in 

 which a period of one to four weeks has intervened between 

 pollination and fecundation. - ^ The attendant remarkably slow 

 development, therefore, seems to be a check upon the unlimited 

 multiplication of individuals. 



(20) MQller. H. Fertilization of Flowers. 539. 1883. 



(21) MQller, H. Loc. cit. 540. 



(22) Morong, T. Contrib. Herb. Colunib. Coll. 1 : 281. 1892. 



(23) Darwin, O. Fertiliz. of Orchids. Ed. «: 289. 1877. 



(24) Lubbocic, J. Flowers, Fruits and Leaves. 3: J894. 



(25) Guignard. Annales Scl. Nat. Bot. VII. 4. 202. 

 (26j Hildebraud, F. Bot. Zeit. 44:331.1863. 



