355 Commonwealth Avenue, 
Boston, Mass., May 2d, 1925. 
My dear Mr. Standleyj 
As I intend to devote the greater part of 
my vacation this summer to a study of the genus Stelis, I set out 
for the mounter the ©hole of your Costa Rican collection, yesterday 
forenoon. I have never before handled such a well preserved set 
of Stelis specimens. It will be a pure joy to work on your material, 
and through its unexampled fullness, to clarify some of the dim 
spots in the Central American representation of the genus. To you 
it may seem that the same species is too frequently represented, 
but for my purposes it is essential that there should be numerous 
examples of everything. Bp to the present time we have had to de¬ 
pend too much on single specimens, in studies of the Central Amer¬ 
ican prehid flora. 
then you receive the list of numbers you will 
be surprised at the small number of specimens that cannot be given 
a name. But I must warn jrou that fruiting material in the orchids 
is next to valueless until one is becoming very familiar with a 
special flora. In vegetative habit, numerous species of Stelis and 
Pleurothallis simply repeat a pattern, while florally they are ex¬ 
traordinarily distinct through great differences. To determine the 
plants that are sterile, one must have a large and almost complete 
over, 
