‘aused the labellum to assume directly opposite posi- 
tions. [t arouses curiosity with regard to the taxonomic 
worth of resupination in the Orchidaceae. It aroused my 
curiosity very much as long ago as 1905, when I studied 
specimens of Malawis monophyllos and Microstylis brachy- 
poda, so-named, in the British Museum of Natural His- 
tory. At that time I regarded resupination as being a 
weak character for the segregation of species in the Or- 
chidaceae.° 
Of course one might argue that resupination or its 
opposite is a strong and reliable diagnostic character be- 
‘ause the orchid flower tends to become resupinate or 
otherwise when, through unusual circumstances, the per- 
ianth is so disposed that the labellum is forced away from 
its accustomed position. However, there is something 
here suggesting the strength of a sexual urge or a tropis- 
tic response rather than a deep-seated structural change. 
Indeed, there has not been any marked structural change 
inthe perianth itself in Malaais monophyllos or its vari- 
ety. The change has occurred in the pedicel. Further- 
more the instability of the resupinate condition as evinced 
by the evolutionary history of Mal/axis paludosa should 
not be overlooked in the consideration of resupination in 
our taxonomic studies of the Orchidaceae, because in con- 
templating the significance of the twisted pedicel perhaps 
our imaginations are sufficiently vivid to conceive of a 
time when Malaais paludosa had non-resupinate flowers ; 
of a time when the flowers were resupinate; of a time, 
when by additional torsion of the pedicel, the flowers re- 
turned to their primitive position. But it would require 
® Professor Fernald in Rhodora 28 (1926) 92 has assumed gratui- 
tously that since Asa Gray described Microstylis brachypoda in 1835, 
students of the orchids have overlooked the difference between the 
plants of eastern America and the Old World, simply because they 
have not reinstated a species which subsequent to 1835 Gray himself 
reduced to synonymy under Microstylis monophyllos. 
[ 180 ] 
