of leaves and in the nature of the roots. Both of these 
characters are genetically determined in 8S. magnicampo- 
rum, and development under wet conditions does not 
alter them. Evenin two specimens from calcareous hang- 
ing fens in Illinois the leaves remained fugacious and the 
roots tuberous. 
In general, it appears that S. magnicamporum is a 
western, prairie counterpart of S. cernua. Although not 
allopatric (indeed, 8. cernua occurs further west than S. 
magnicamporum in several areas), S. magnicamporum is 
the more prevalent in the west and is better adapted to 
the droughty conditions of the area than is S. cernua, 
which often relies upon local abundance of moisture for 
its survival, 
‘The two species, are, however, truly sympatric only on 
rare occasions, for even where occurring at the same sta- 
tion these species are spatially isolated by ecological fac- 
tors. Of the two ecotypes of var. cernua that I have been 
able to distinguish in the Illinois region, one occurring 
principally in moist sand prairie, the other in dry open 
woods and old fields on finer textured soils, usually only 
the former occurs with S. magnicamporum. At such sta- 
tions 8. magnicamporum occupies the dry ridge tops and 
S. cernua the wetter swales. Both of these taxa occur in 
calcareous hanging fens, but S. magnicamporum does so 
very rarely, only two such stations being known, and I 
have never seen them associated at such a site. Sprranthes 
magnicamporum is further isolated from this sand prairie 
ecotype of S. cernua, at least in the southern Lake Mich- 
igan region, by season, as these S. cernua populations 
bloom from mid-August to mid-September, whereas in 
S. magnicamporum anthesis is initiated usually in mid- 
September and continues into October. Floral fragrance 
(which is lacking in this ecotype of S. cernwa) may like- 
wise serve to isolate these taxa. 
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