Salix exigua Nutt. Salix exigua Nutt., N. Amer. Sylv. 1(2): 75. 1842 sec. Argus & al. 2010=Salix interior var. angustissima (Andersson) Dayton in Techn. Bull. U.S.D.A. 420: 78, f. 42. 1934 syn. sec. The Plant List 2013