THE ORCHIDS OF NEW EX G LAX P. 



23 



M tiller's stupendous work, The Fertilization of Flozvers (it has 

 recently been translated from the German) gives very clear and 

 plausible reasons for the concealment of the 

 pollen and the peculiar formation of the 

 nectaries in plants, and I am sure it will 

 add to the reader's pleasure in studying the 

 Showy Orchis if I insert some extracts. 



"Freely exposed, pollen is liable to be Fig . 5 ._ Head of Moth , 

 spoilt by rain, devoured by flies and beetles, Acontia luctuosa, 



J with pollen-masses at- 



or carried away by pollen-collecting bees. tached to its proboscis. 



Pollinium removed by 



Of these contingencies, the first is wholly a pencil and before un- 



... , , dergoing the movement 



an evil, the second becomes advantageous f depression. (Both 

 if any considerable amount of pollen is fromDarwm.) 

 conveyed to the stigma, and the third almost always results 

 in fertilization, and is therefore altogether advantageous. 

 Concealment of the pollen, as of the honey, must have been 

 brought about, in the first place, as a protection from rain. 

 Since with this advantage comes the disadvantage that the 

 sheltered pollen is less likely to be touched and placed on the 

 stigma by insect visitors, concealment of the stamens has not 



become general And all flowers with hidden anthers 



have only been able to shelter their pollen from rain in so far 

 as they have developed other adaptations for particular visitors, 

 which compensate for the less general access of pollen-carrying 

 insects. For this reason, flowers with hidden pollen (Orchids, 

 for instance) afford the most conspicuous examples of adapta- 

 tion in form and in dimensions to a more or less narrow circle 

 of visitors. But the more perfectly flowers are adapted for 

 cross-fertilization by particular insects, the more unlikely does 

 it become that other insects visiting the flowers will effect 

 cross-fertilization, and the more will such visits of other insects 

 be useless or injurious. So concealment of the pollen is useful 

 (to a subsidiary degree) in limiting insect visitors. 

 The mechanism is so perfect and so effectual in these flowers, 



