Entry From
Flora of North America, Vol 23,
Discussion
Carex bigelowii is a highly variable, circumpolar species complex with four subspecies recognized in Europe (A. O. Chater 1980). The North American populations can be divided into an eastern and a western taxon, which cannot always be distinguished morphologically. They are recognized as two subspecies of a widely ranging complex for this treatment.
Carex bigelowii appears to be closely related to the western montane C. scopulorum; it is distinguished by its narrower leaves and narrower, ellipsoid perigynia. Tall plants of C. bigelowii may be confused with C. aquatilis (especially C. aquatilis var. minor) and can be distinguished by the short bracts, hypostomic leaves, and dull achenes of C. bigelowii. These two taxa have been reported to hybridize (M. G. Duman and S. D. Kryszczuk 1958) and have been artificially hybridized by J. S. Faulkner (1973), who found that these two species were very closely related.