ClIAF. Y. PLEUROTHALLIS PROLIFERA. 135 



been carried away. Insects sometimes remoTe only 

 one of the two pairs. I noticed a flower with all four 

 pollen-leaves still in place, with a single one in the 

 stigmatio cavity; and this must clearly have been 

 brought by some insect. Within the stigmas of many 

 other flowers pollen-leaves were observed. The plant 

 produces plenty of seed ; and thirteen of the twenty-one 

 lower flowers on one spike had formed large capsules. 



We will now turn to some exotic genera. The pol- 

 linia of Pleurothallis prolifera and ligulata (?) have a 

 minute caudicle, and mechanical aid is requisite to 

 force the viscid matter from the under side of the 

 rostellum into the anther, thus to catch the caudicles 

 and remove the poUinia. On the other hand, in our 

 British Malaxis and in Miorostylis rhedii from India, 

 the upper surface of the minute tongue-shaped ros- 

 tellum becomes viscid and adheres to the poUinia 

 without any mechanical aid. This appears likewise to 

 be the case with Stelis racemiflora, but the flowers were 

 not in a good state for examination. I mention this 

 latter flower partly because some insect in the hot- 

 house at Kew had removed most of the pollinia, and 

 had left some of them adhering to the lateral stigmas. 

 These curious little flowers are widely expanded and 

 much exposed ; but after a time the three sepals close 

 together with perfect exactness, so that it is scarcely 

 possible to distinguish an old flower from a bud : yet, 

 to my surprise, the closed flowers opened when im- 

 mersed in water. 



The allied MasdevaUia fenestrata bears an extra- 

 ordinary flower. The three sepals instead of closing, 

 as in the case of Stelis after the flower has remained 

 s„for a time expanded, cohere together and never open. 

 Two minute, lateral, oval windows (hence the name 

 fenestrata), are seated high up the flower opposite each 



