Chap. V. PLEUEOTHALLIS PEOLIFERA. 135 



been carried away. Insects sometimes remove oniy 

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

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

 stigmatic cavity ; and this must clearly have been 

 brought by some insect. Within the stigmas of many 

 other flowers pollen-leaves were observed. The plant 

 l^roduces 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 Plturothallis i^'^'oUftra 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 pollinia. On the other hand, in our 

 British Malaxis and in MicrosUjlis rhedii from India, 

 the upjjer surface of the minute tongue-shaped ros- 

 tellum becomes viscid and adheres to the pollinia 

 without any mechanical aid. This appears likewise to 

 be the case with Stelis racemijlora, 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 Masdevallia fenestrata bears an extra- 

 ordinary flower. The three sepals instead of closing, 

 as in the case of Stelis after the flower has remaino*! 

 f(n' a time expanded, cohere together and never open. 

 T\vo minute, lateral, oval windows (hence the name 

 fenestrata), are seated high up the flower opposite eacli 



