200 



the vestigial remains of the former bifid apex. This basal 

 lobe is rudimentary in some specimens of P. Australe, while 

 in the case of F. rotundifloruni it is separated from the 

 anterior part of the appendage by a singular finger-like pro- 

 cess, a feature which readily serves to distinguish that species 

 from all other known forms. 



In the great majority of our species the stigmatic sur- 

 face is reniform, with the hilum towards the rostellum, 

 although this shape is sometimes departed from, as in the 

 case of F. Australe and F. iiigricans. 



Fitzgerald is probably correct when he says that all 

 members of this genus are fertilized by insects. Wherever' 

 I have had the opportunity to cultivate specimens under con- 

 ditions such as would exclude insects, fertilization did not 

 take place. In the case of F. Australe, however, the 

 mechanism is such that self-fertilization might conceivably 

 occur, although I have not yet been able to determine whe- 

 ther it is ever effected in this particular way. The small 

 members of the genus are frequently visited by minute forms 

 of Staj^hylinidas and other small insects ; while insects large 

 and small frequent the larger flowers. I have in -the latter 

 case actually observed the fertilization of the plant by bees. 



The disposition of the callous portion of the labellum as 

 to area, abruptness, or otherwise of termination, degree of 

 elevation above the membranous part, is important from a 

 diagnostic standpoint. These features are far more constant 

 than one might a jii'^'^i'i suppose. On the other hand, the 

 degree of flexion of the labellum in different individuals of 

 P. liatens varies exceedingly. 



The angle of attachment which the flower makes with 

 the vertical axis of the spike is a feature that seems to 

 have escajDed attention, except perhaps in some of the very 

 minute forms in which the flowers are deflexed. In some 

 cases the angle thus made is very small, the flower lying 

 almost in apposition with the axis. In others the flower 

 diverges considerably, the angle being comparatively large. 

 The outstanding flowers of F. fuscum and P. Fitzgeraldi, 

 for instance, afford a ready means of distinguishing them in 

 the field from their respective allies, P. patens and P. pruin- 

 osum. 



With all due deference to Bentham, who seems to hold 

 a different view (''Flora Aust.," vol. vi., p. 340), some diag- 

 nostic importance miist be attached to odour. The strong, 

 delightful odour of the tiniest specimen of P. Fitzgeraldi 

 would as surely distinguish it from F . fuscum and P . pruin- 

 osutn as that of a magnolia from its inodorous allies. 



