Memoirs of The New York Botanical Garden
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of Vascular Plants of Northeastern United States and adjacent Canada
Details: Philonotis caespitosa Jur.
Buck, William R. 1987. Bryostephane Steereana: A Collection of Bryological Papers Presented to William Campbell Steere On The Occasion of His 80th Birthday. Mem. New York Bot. Gard. 45: 1-749.
Philonotis caespitosa Jur.
New to the Yukon. Although often considered a variety of P. fontana, this seems a distinct species in its own right.