Publication: Phytologia. 77: 284. 1995.
selected vouchers: WTU
Notes: FNA20: "This variety has been treated mostly as a distinct species in floras. Character ranges overlap considerably with var. lanceolatum, and it is often difficult to distinguish the two entities where their distributions overlap. In areas of sympatry, the two taxa hybridize to form septaploid plants (2n = 56)."