References for Urticaceae
Bassett, I.J., C.W. Crompton and D.W. Woodland. 1974. The family Urticaceae in Canada. Can. J. Bot. 52:503-516.
Boufford, D.E. 1997. Urticaceae. In Flora of North America Editorial Committee, eds. Flora of North America North of Mexico - Volume 3. Magnoliophyta: Magnoliidae and Hamamelidae. Oxford Univ. Press Inc. New York, NY.
Hermann, F.J. 1946. The perennial species of Urtica in the United States east of the Rocky Mountains. Amer. Midl. Nat. 35:773-778.

Source for the Reference Lists

George W. Douglas, Del Meidinger and Jim Pojar. 1998-2002. Illustrated Flora of British Columbia.