This globally rare species is largely restricted to remnants of native grassland in the southern Interior Low Plateaus and the west Gulf Coastal Plain (FNA 19). It is considered threatened or endangered in all states except Texas, where it is concentrated around the "Big Thicket" (K). In Ky., it is known only from TRIG, in Fort Campbell and Land-Between-the-Lakes. N. barbatus appears close to serpentarius and roanensis; these species share lower leaves deltate to elliptic; phyllaries 5-10, coarsely setose; and florets 5-15. N. barbatus is distinguished by its lower leaves unlobed and coarsely dentate or serrate (versus 3-5 lobed); and phyllaries purple or lavender (versus usually green or sometimes purple in serpentarius)