212 VANDE^, Chap. VU 



likewise attractive to insects. In the drawing (fig. 32) 

 the labellum has been forcibly raised a little up, so as 

 to show the depression and the bent filament. In its 

 natural position it may almost be compared to a huge 

 cocked-hat, supported by a footstalk and placed on the 

 head of the column. 



The twisting of the column, which I hare seen in 

 no other Orchid, causes all the important organs of 

 fructification in the flowers on the left side of the 

 spike to face to the left, and. in all those on the right 

 side to face to the right. So that two flowers taken 

 from opposite sides of the same spike and held in 

 the same relative position are seen to be twisted in 

 opposite directions. One single flower, which was 

 crowded by the others, was barely twisted, so that its 

 column faced the labellum. The labellum is also 

 slightly twisted : for instance, in the flower figured, 

 wliich faced to the left, the midrib of the labellum was 

 first twisted to the right-hand, and then to the left, but 

 in a less degree, and being bent over it pressed on the 

 posterior surface of the crooked summit of the column. 

 The twisting of all the parts of the flower commences 

 in the bud. 



The position thus acquired by the several organs is 

 of the highest importance; for if the column and 

 labellum had not been twisted laterally, the poUinia, 

 when shot forth, would have struck the overarching 

 labellum and have then rebounded, as actually oc- 

 curred with the single abnormal flower having a nearly 

 straight column. If the organs had not been twisted 

 in opposite directions on the opposite sides of the same 

 crowded spike, so as always to face to the outside, there 

 would not have been a clear space for the ejection of 

 the poUinia and their adhesion to insects. 



When the flower is mature the three sejmls hang 



