v.] REMARKABLE LEA VES. 87 



perish on being brought into the lower and warmer 

 zones. One species is known as the Butterfly Orchis 

 (Oncidium papilio] from the appearance of its flowers. 

 The clusters or panicles of flowers are in some 

 species of an enormous size ; in more than one species 

 they reach the length of twenty feet, whilst the flowers 

 themselves are three inches across. Peristeria elata, 

 a Central American species, is locally known as " El 

 Spirito Santo," from the resemblance of the column 

 and its appendages to a dove. 



In the genus Catasetum there is a peculiar contriv- 

 ance to effect cross-fertilisation. In this species the 

 column bears at about its middle two long sensitive 

 projections, to which Mr. Darwin has applied the 

 term antenna. The labellum, or lip, is thick and 

 fleshy, and the bees visit it in order to gnaw its 

 edges. In so doing they touch the antenna, which 

 transmits a vibration " to a certain membrane, which 

 is instantly ruptured ; this sets free a spring, by which 

 the pollen mass is shot forth, like an arrow, in the 

 right direction, and adheres by its viscid extremity 

 to the back of the bee. The pollen mass of the male 

 plant (for the sexes are separate in this orchid) is 

 thus carried to the flower of the female plant, where 

 it is brought into contact with the stigma, which is 

 viscid enough to break certain elastic threads, and 

 retaining the pollen, fertilisation is effected." Dar- 

 win, " Origin of Species" p. 155. 



More remarkable still i'n this connection is the 

 extraordinary contrivance in a species of orchid 

 called Cory ant kes, lately described by Dr. Criiger and 

 referred to by Mr. Darwin, from whom we quote the 



