Chap. I a. 



PTEEOSTYLIS LONGIFOLIA. 



87 



whicli is thus temporarily imprisoned within the other- 

 wise almost completely closed flower. The lahellum 



Fig. 14. 



Pteeosttlis longhfolia. (Copied from Mr. E. D. Fitzgerald's 'Australian 

 Orchids.*) 



A. Flower in its natural state : the 



outline of the column is dimly 

 seen within. ' 



B. Flower with the near lateral 



petal removed, showing the 



column with its two shields, 

 and the labellum in the position 

 which it occupies after having 

 been touched. 



remains shut from half an hour to one hour and a 

 half, and on reopening is again sensitive to a touch. 

 Two membranous shields project on each side of the 



