CamBrRIDGE, Massacuusetrts, Marcu 6, 1935 
BOTANICAL MUSEUM LEAFLETS 
HARVARD UNIVERSITY 
A FOURTH POLYMORPHIC ALLIANCE 
IN EKPIDENDRUM 
BY 
Oakes AMEs, F. Tracy Husparp 
AND CHARLES SCHWEINFURTH 
TrrouGuour our studies of North American Epi- 
dendrum, one group of species has been a constant source 
of perplexity. In part this perplexity has arisen from an 
inadequate knowledge of the types, and in still greater 
measure from the variability and close affinity of the 
species. The first difficulty (inadequate knowledge of the 
types) has been removed by the receipt of flowers from 
the types of H’pidendrum oncidioides Lindl., 1. graniti- 
eum Lindl., £.gravidum Lindl., #. Mooreanum Rolte 
and HE. profusum Rolfe, for which we have to thank Sir 
Arthur W. Hill, Director of the Royal Botanic Gardens, 
Kew, and of a flower from the type of 7. guatemalense 
Klotzsch which was kindly sent to us by Dr. Rudolf 
Mansteld of the Botanisches Museum, Berlin-Dahlem. 
The second source of confusion (variability and close af- 
finity of the species) has been gradually eliminated by the 
receipt of more material, among which were certain link- 
ing forms, and by acritical study of the various elements. 
‘These comparisons and the true interpretation of former- 
ly uncertain types have led us to believe that here again 
we are dealing, not with several distinct species, but with 
an alliance composed of varying forms of a single poly- 
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