INTRODUCTION. 3 



actions' for 1854. Dr. Hooker has given a full and 

 accurate account, with drawings, of the structure of 

 the parts ; but from not having attended to the agency 

 of insects, he did not fully understand the object 

 gained. Eobert Brown,* in his celebrated paper in the 

 ' Linnean Transactions,' expresses his belief that insects 

 are necessary for the fructification of most Orchids; 

 but adds, that the fact of- all the capsules on a dense 

 spike not infrequently producing seed, seems hardly 

 reconcilable with this belief: we shall hereafter find 

 that this doubt is groundless. Many other authors 

 have given facts and expressed their belief, more or 

 less fully, on the necessity of insect-agency in the 

 fertilisation of Orchids. 



In the course of the following work I shall have the 

 pleasure of expressing my deep obligation to several 

 gentlemen for their unremitting kindness in sending 

 me fresh specimens, without which aid this work would 

 have been impossible. The trouble which several of 

 my kind assistants have taken has been extraordinary: 

 I have never once expressed a wish for aid or for in- 

 formation which has not been granted me, as far as 

 possible, in the most liberal spirit. 



EXPLANATION OF TEEMS. 



In case any one should look at this treatise who has 

 never attended to Botany, it may. be convenient to 

 explain the meaning of the common terms used. In 

 most flowers the stamens, or male organs, surround in 

 a ring the one or more female organs, called the pistils. 

 In all common Orchids there is only one well-developed 

 stamen, which is confluent with the pistils, and they 



' Linnean Transactions,' 1833, vol. xvi. p. 704. 



