Verbatim text: Wagner, W. H. Jr. 1973. Reticulation of holly ferns (Polystichum) in the western United States and adjacent Canada. Amer. Fern J. 63: 99--115.
Author: Wagner, W.H. Jr.
Year: 1973
Title: Reticulation of holly ferns (Polystichum) in the western United States and adjacent Canada
Journal: Amer. Fern J
Volume: 63
Pages: 99–115