CuAP. VII. CATASETUM. 191 



the poUinium is shot forth, the large spike-like anther 

 is generally carried with it. If the disc strikes a flat 

 surface like a table, the momentum from the weight 

 of the "anther often carries the pollen-bearing end 

 beyond the disc, and the poUinium is thus affixed in 

 a wrong direction for the fertilisation of another 

 flower, supposing it to have been attached to an 

 insect's body. The flight of the pollinium is often 

 rather crooked.* But it must not be forgotten that 

 under nature the ejection is caused by the antennae 

 being touched by a large insect standing on the la- 

 bellum, which will thus have its head and thorax 

 placed near to the anther. A rounded object thus 

 held is always accurately struck in the middle, and 

 when removed with the pollinium adhering to it, the 

 weight of the anther depresses the hinge of the pol- 

 linium; and in this position the anther-case readily 

 drops off, leaving the balls of pollen free, in a proper 

 position for fertilising the female flower. The utility 



* M. Baillon (' Bull, de la Soe. quetit and progreasivo retraction 



Bot. de France,' torn. i. 1851, p. of the pedicel, the pollen-masses 



285) states that Catasetum luridum might be carried into the stigmatic 



ejects its poUinia always in a chamber. This is not possible in 



straight line, and in such a direc- the three species whii^h I have 



tion that it sticks fast to the examined, and would be useless, 



bottom of the concavity of the But M.Meniere himself then goes 



labellum ; and he imagines that on to show how important insects 



in this position it fertilises the are for the fertilisation of Orchids; 



Uower in a manner not oleaily and apparently infers that their 



explained. In a subsequent paper agency comes into play with 



in the same volume (p. 3B7) M. Catasetum, and that this plant 



Me'nifere justly disputes M. Bail- does not fertilise itself. Both M. 



Ion's conclusion. He remarks Baillon and M. Meniere correctly 



that the anther-case is easily de- describe the curved position in 



tached, and sometimes naturally which the elastic pedicel lies 



detaches itself ; the poUinia then before it is set free. Neither of 



swing downwards by the elasticity these botanists seems to be awaie 



of the pedicel, the viscid disc still tliat tba species of Catasetum 



remaining attached to the roof (ut least the five which I have 



of the stigmatic chamber. M. examinedj aje exclusively male 



Me'niere hints that, by the subse- plants. 



