42 THE ORCHIDS OF NEW ENGLAND. 



was formed." He mentions, however, one British species, 

 Herminium monorchis, " which has two separate and large 

 discs," and also " a crest or solid ridge, more plainly developed 

 than might have been expected ; " and have we not in our H. 

 Hookcri a similar instance ? 



" Habenaria chlorantha depends," says Darwin, "on the 

 larger nocturnal Lepidoptera," and he shows the contrivances 

 for securing fertilization to be even more interesting than in 

 Orchis spectabilis. " The two anther cells are separated by a 

 wide space of connective membrane, and the pollen-masses are 

 enclosed in a backward, sloping direction. The viscid discs 

 front each other and stand in advance of the stigmatic surface. 

 Each disc is circular, and in the early bud consists of a mass of 

 cells of which the exterior layers (answering to the pouch in 

 Orchis) resolve themselves into matter which remains adhesive 

 for at least twenty-four hours after the pollen-mass has been 

 removed." The stalk, or caudicle, of the pollen-mass does not 

 rise directly out of the flat side of the viscid " button," like the 

 stem on a cherry, but is attached to it by " a short drum-like 

 pedicel or continuation of the membranous portion of the disc ; " 

 the shank of the button, to carry out the simile. This stalk is 

 united " in a transverse direction to the embedded end of the 

 drum, and its extremity is prolonged, as a bent rudimentary 

 tail, just beyond the drum. The stalk is thus united to the 

 viscid disc in a plane at right angles. The drum-like pedicel is 

 of the highest importance, not only by rendering the viscid disc 

 more prominent, but on account of its power of contraction. 

 The pollinia lie inclined backward in their cells, above and some 

 way on each side of the stigmatic surface : if attached in this 

 position to the head of an insect, the insect might visit any 

 number of flowers and no pollen be left," the pollinia " striking 

 against the anther-cells." But in a few seconds after the pol- 

 linium is removed " and the inner end of the drum-like pedicel 

 exposed to the air, one side of the drum contracts and draws 



