Verbatim text: Watson, T. J. 1977. The taxonomy of Xylorhiza (Asteraceae–Astereae). Brittonia 29: 199–216.
Author: Watson, T.J.
Year: 1977
Title: The taxonomy of Xylorhiza (Asteraceae–Astereae)
Journal: Brittonia
Volume: 29
Pages: 199–216