V 
THE FLORAL ANATOMY OF THE URTICALES 
Albert Reiff Bechtel 
(Received for publication February 9, 192 1) 
In the search for natural relationships in the seed plants, the morpholo- 
gist and the anatomist have contributed much to the subject from work on 
the reproductive mechanism and on the structure of the vegetative organs. 
During recent years the breeder and the geneticist have presented theories 
based on experimental evidence which the taxonomist can not ignore. The 
subject of flower anatomy, however, has been limited in workers and in 
material studied. This subject should have contributions of value to offer 
for principles that are to be the guides in determining relationships within 
the angiosperms, as well as casting more light on the floral characters of the 
ancestors of the angiosperms. 
There is as yet no definite knowledge of the ancestry of the various 
divisions of the angiosperms. Here hypotheses must be made from the 
study of external form upon which the classification has been mainly based, 
and these hypotheses must be strengthened or weakened by evidence from 
internal structure. 
Different views have been held as to what the primitive flower was like. 
De Candolle (6) looked upon the primitive flower as hermaphroditic with 
all parts free. Engler (9) considered the simple, naked, unisexual flower 
as the primitive type. Bower proposed a bisexual flower with many 
sporophylls surrounded by one whorl of floral envelopes. The types of 
flowers known to us have been derived from ancestors, undoubtedly, like 
unto one or more of those above described, by the processes of amplification 
and reduction, which processes students of natural history accept as the 
great factors in molding our present forms of life. 
Two cautions are suggested by Engler and Gilg (10) for st^udents of 
phylogenetic relationships to heed: first, the consideration of a simple 
structure as primitive when it is reduced; second, the placing of reduced 
forms because of their reduction, too high in rank. There is a guide in this 
matter of interpreting reduced forms in Bower's (4) definitions: 
Where the development of the natural organism, either in whole or in part, in external 
form or internal structure, falls short of that of the ancestry, that condition would be 
described as reduced. 
Examples from among the earlier workers of the contribution of floral 
anatomy to the knowledge of the morphology and relationships of angio- 
sperms are the following. In 1862, Darwin (5) declared the discovery of the 
nature of the orchid flower by studying transverse and longitudinal sections. 
His conclusions drawn at that time constitute our present interpretation 
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