Reference:Rydberg1908d
Verbatim text: Rydberg, P. A. 1908b. Poteridium. In: N. L. Britton et al., eds. 1905+. North American Flora.... 47+ vols. New York. Vol. 22, p. 388.
Author: Rydberg, P.A.
Year: 1908b
Title: Poteridium
Editor: Britton, N.L.
Book year: 1905
Book title: North American Flora
Book volume: 47+ vols
Volume: 22
Pages: 388