This rather poorly known segregate is distinguished by having relatively narrow, basally-concentrated leaves and elongated upper internodes. It occurs on damp sandy soils, including open boggy sites and sandy river-banks, from sw. N.C. to ne. Tex. and north to s. Ill. (Wherry 1955; Correll & Johnson 1970; W). Wherry mapped it on the Coastal Plain within w. Ky. (included here as imprecise uncertain locations). Within this region, JC and P. Zale recently discovered it in the flatwoods of MARS (Sharp-Elva Road). There also appears to be a coll. of this taxon from MCRE, "on sandstone shelf at Pitch Rapid" of Cumberland Rv. (R. Jacobs #205801 at EKY). Wherry (1955) noted "late spring" for the blooming period of angusta, but the MARS plants (noted above) bloomed in Jun-Jul of 2012, when transferred to cultivation. Flowering colls. from the Cumberland Plateau are dated even later: Jul 23 (MCRE); Jul 29 (on banks of Daddy's Creek in Cumberland Co., Tenn.); Oct 10 (on banks on Obed River in Morgan Co., Tenn.); and see other colls. at TENN. P. Zale (pers. comm.) has found a wide range of flowering by ssp. angusta in cultivation, from late May to mid-Nov.