CuAP. I. ORCHIS MASCULA. 13 



the same or into another nectary : by looking at the 

 diagram (fig. 1, A) it will be evident that the firmly 

 attached pollinium will be simply pushed against or 

 into its old position, namely, into the anther-cell. 

 How then can the flower be fertilised? This is 

 effected by a beautiful contrivance : though the viscid 

 surface remains immovably affixed, the apparently 

 insignificant and minute disc of membrane to which the 

 caudicle adheres is endowed with a remarkable power 

 of contraction (as will hereafter be more minutely 

 described), which causes the pollinium to sweep 

 through an angle of about ninety degrees, always in 

 one direction, viz., towards the apex of the proboscis or 

 pencil, in the course of thirty seconds on an average. 

 The position of the pollinium after the movement is 

 shown at B in fig. 2. After this movement, completed 

 in an interval of time which would allow an insect to 

 fly to another plant,* it will be seen, by turning to the 

 diagram (fig. 1, A), that, if the pencil be inserted into 

 the nectary, the thick end of the pollinium now 

 exactly strikes the stigmatic surface. 



Here again comes into play another pretty adapta- 

 tion, long ago noticed by Eobert Brown.f The 

 stigma is very viscid, but not so viscid as when 

 touched by a pollinium to pull the whole off an insect's 

 head or off a pencil, yet sufficiently viscid to break 

 the elastic threads (fig. 1, F) by which the packets 

 of pollen-grains are tied together, and leave some of 

 them on the stigma. Hence a pollinium attached to 

 an insect or to a pencil can be applied to many 

 stigmas, and will fertilise all. I have often seen the 



* Dr. H. Miiller ('Die Befruch- flowers of Orchis mancula, and 



tuns; der Blumen durch lusekten,* finds that this t^tatement is correct. 



IS73, p. 84) has timed humble- f ' Transactions of the Linnean 



bees at work on the spikes of Society,' vol. xvi. p. 731. 



