Verbatim text: Tyrl, R. J. 1975. Origin and distribution of polyploid Achillea (Compositae) in western North America. Brittonia 27: 187–196.
Author: Tyrl, R.J.
Year: 1975
Title: Origin and distribution of polyploid Achillea (Compositae) in western North America
Journal: Brittonia
Volume: 27
Pages: 187–196