A. A.  Heller, Catalogue of North American plants north of Mexico, exclusive of the lower cryptogams. New York: The New York Botanical Garden, 1900.

A. A.  Heller, Catalogue of North American Plants North of Mexico, exclusive of the lower Cryptogams. Minneapolis (?): University of Minnesota (?), 1898, p. 5.

A. A.  Heller, ?New combinations - XI?, Muhlenbergia, vol. 9, pp. 67 - 68, 1913.