BOTANICAL MUSEUM LEAFLETS 
HARVARD UNIVERSITY 
CampripGe, MAssacuuseTts, JULY 27, 1948 VoL. 13, No. 4 
VASCULAR ANATOMY OF ORCHID 
FLOWERS 
BY 
B. G. L. Swamy 
Biological Laboratories, Harvard University 
Tuar the structural complexities of a flower can be 
made clear by astudy of floral anatomy in relation to its 
vascularization is becoming a prevalent thought. While 
such a study is being concentrated on the members of 
several other natural orders, orchids, characterized by 
their ‘‘over-specialized’’ floral organization, still remain 
to be attacked from this angle. 
Robert Brown (1831) was the first to elucidate the 
nature of the orchid flower. He compared it with the 
structural and other morphological features of the flowers 
of certain allied monocotyledonous families and inter- 
preted the labellum as a compound structure made up of 
the lateral stamens of the outer whorl and the median 
petal. Darwin, after studying the course of vascular 
traces in a considerable number of orchid flowers belong- 
ing to different tribes, incorporated the results in his 
monograph, ‘“The Various Contrivances by which Or- 
chids are Fertilised by Insects’’ (ed. 1899). In general, 
he confirmed Brown’s observations, particularly with re- 
gard to the compound nature of the gynostemium and 
labellum. 
Subsequent to this publication, very little has been 
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