Monographs Details: Acacia angustissima var. hirta (Nutt.) B.L.Rob.
Authority: Isley, Duane. 1973. Leguminosae of the United States: I. Subfamily. Mimosoideae. Mem. New York Bot. Gard. 25 (1): 1-152.
Discussion:Acacia hirta Nutt. Acaciella hirta (Nutt.) Britt. & Rose Acacia filicioides auct. Texas, n to Missouri, e (apparently disjunctly) to Florida. Western: prairie grassland, roadsides, open woodlands, usually alkaline soil. Eastern: open wood lands, glades, bluffs, limestone or shale ledges and outcrops. May-July or (Florida) August-Sept. Mexico and Central America. The circumscription of var. hirta has been presented elsewhere (Isely, 1969).