Chap. VII. CATASETUM. 187 



excitement wliich causes the disc to separate from the 

 surrounding parts, include some made on the following 

 species. Several flowers were sent me by post and by 

 the railroad, and must have been much jarred, but 

 they had not exploded. I let two flowers fall from a 

 height of two or three inches on the table, but the 

 poUinia were not ejected. I cut off with a crash with 

 a pair of scissors the thick labellum and ovarium 

 close beneath the flower ; but this violence produced 

 no effect. Nor did deep pricks in various parts of the 

 column, even within the stigmatic chamber. A blow, 

 sufficiently hard to knock off the anther, causes the 

 ejection of the pollinium, as occurred to me once 

 by accident. Twice I pressed rather hard on the 

 pedicel, and consequently on the underlying ■ ros- 

 tellum, without any effect. Whilst pressing on the 

 pedicel, I gently removed the anther, and then the 

 pollen-bearing end of the pollinium sprang up from 

 its elasticity, and this movement caused the disc to 

 separate. M. Meniere,* however, states that the 

 anther-case sometimes detaches itself, or can be gently 

 detached, without the disc separating ; and that then 

 the upper end of the pedicel, bearing the pollen-masses, 

 swings downwards in front of the stigmatic chamber. 



After trials made on fifteen flowers of three species, 

 I find that no moderate degree of violence on any 

 part of the flower, except on the antennae, produces 

 any effect. But when the left-hand antenna of G. 

 saccatum, or either antenna of the three following 

 species, is touched, the pollinium is instantly ejected. 

 The extreme tip and the whole length of the antennae 

 are sensitive. In one specimen of G. tridentatum a 

 touch from a bristle sufficed ; in five specimens of 



* ' Bull, (le la Soc. Bot. de France,' torn. i. 1854, p. 367. 



