a distinct species, and taxonomists have not been unani- 
mous in accepting Correll’s treatment. 
Variety ochroleuca (Rydb.) Ames is poorly understood, 
and there has been much uncertainty concerning its sta- 
tus. It may be distinguished by its yellowish, strongly 
fragrant flowers and long floral bracts, the lower ones of 
which exceed the flowers in length. It is said to produce 
monoembryonic seeds, in contrast to the polyembryony 
characteristic of typical S. cernua. Its distribution has 
been variously restricted to east of the Appalachians or 
expanded to include the entire range of the species. 
Other species and varieties have been proposed in this 
complex, but all have been referable, at least in the ab- 
sence of a thorough study of possible ecotypic differenti- 
ation in this species, to the var. cermwa complex, to var. 
odorata, or to other species. 
It is thus only with caution that one would describe 
a new taxon in this complex, for the danger of intro- 
ducing additional confusion is great. However, if pro- 
gress is to be made in our understanding of the group, 
some risk must be taken, and, in the hope that it will 
aid in aclarification of the situation, | am describing the 
following species. My understanding of this species and 
the S. cernua complex as a whole is based on fourteen 
vears of field experience principally in Illinois and sur- 
rounding areas and on the study of hundreds of herbari- 
um specimens from all parts of the range of the complex. 
During this period, the habitats of the complex were 
studied in detail, and three habitat groups emerged. 
Further study revealed that morphologically distinct 
populations were restricted to the various habitats, thus 
indicating the presence of taxonomic differentiation 
within the complex. ‘lwo of the three evident taxa are 
here considered to be ecotypes of S. cernua. The third, 
however, has proven distinct enough to warrant specific 
rank. 
[ 286 | 
