66 OPHRE^. Chap. IL 



the two following species of Habenaria : this was well 

 shown by the state of specimens which had been kept 

 in spirits of wine. This weakness apparently stands in 

 relation to the viscid matter of the discs not setting 

 hard and dry as in Orchis; so that a moth with a 

 pollinium attached to its proboscis might be enabled to 

 visit several flowers without having the whole polli- 

 nium dragged off by the first stigma which was struck. 

 The two strap-shaped discs lie close together, and form 

 the arched roof of the entrance into the nectary. 

 They are not protected, as in Orchis, by a lower lip or 

 pouch, so that the structure of the rostellum is simpler. 

 When we come to treat of the homologies of the ros- 

 tellum we shall see that this difference is due to a 

 small change, namely, to the lower and exterior cells 

 of the rostellum resolving themselves into viscid 

 matter ; whereas in Orchis the exterior surface retains 

 its early cellular or membranous condition. 



As the two viscid discs form the roof of the mouth of 

 the nectary, and are thus brought down near to the 

 labellum, the two stigmas, instead of being confluent 

 and standing beneath the rostellum, as in most of 

 the species of Orchis, are lateral and separate. These 

 stigmas consist of protuberant, almost horn-shaped, 

 processes on each side of the nectary. That their 

 surfaces are really stigmatic I ascertained by finding 

 them deeply penetrated by a multitude of pollen- 

 tubes. As in the case of Orchis 'pyramidalis, it is a 

 pretty experiment to push a fine bristle straight into 

 the narrow mouth of the nectary, and to observe how 

 certainly the narrow elongated viscid discs, forming 

 the roof, stick to the bristle. When the bristle is 

 withdrawn, the pollinia adhering to its upper side 

 are withdrawn ; and as the discs form the sides of 

 the arched roof, they adhere somewhat to the sides 



