§ 2. Perennials; receptacle convex or at length low-conical; lower leaves usually opposite.
[*] Involucral scales loose, becoming squarrose, narrowly lanceolate, pointed (½´ long); disk usually purple or brownish; leaves linear, 1-nerved.
3. H. orgyàlis, DC. Stem glabrous, tall, very leafy; leaves mostly alternate, linear to filiform and entire, or the lowest lanceolate and serrulate; scales filiform-attenuate.—Dry plains, Mo. to Neb., south and westward.
4. H. angustifòlius, L. Stem slender (2–6° high), usually scabrous; leaves long and linear, sessile, entire, with revolute margins; heads loosely corymbed, long-peduncled; scales acute or pointed.—Low pine barrens, N. J. to Ky., and southward.
[*][*] Involucral scales closer, more imbricated, short, unequal and not foliaceous; leaves lanceolate to ovate, mostly opposite and 3-nerved.
[+] Disk dark.
5. H. atròrubens, L. Rough-hairy; stem slender (2–4° high), smooth and naked and forking above; leaves thinnish, ovate or oval to oblong-lanceolate, or the lowest heart-shaped (3–6´ long), serrate, abruptly contracted into a margined petiole; heads small, corymbed; scales ovate, obtuse, ciliolate, appressed; rays 10–16; pappus of 2 fringed scales.—Dry soil, Va. to Ark., and southward.
6. H. rígidus, Desf. Stem stout (2–6° high or more), simple or sparingly branched, rough; leaves very thick and rigid, rough both sides, oblong-lanceolate, usually pointed at both ends, nearly sessile, entire or serrate, the lowest oval; heads nearly solitary, pretty large; scales ovate or oblong, obtuse, or mostly acute, ciliate, appressed; rays 20–25, pappus of 2 large and often several small scales.—Dry prairies, Mich. to Ill., and westward.
[+][+] Disk yellow.
7. H. lætiflòrus, Pers. Closely resembling the last; leaves rather thinner; heads single or corymbed; scales rather fewer (in 2 or 3 rows), narrower and acute or mostly acuminate.—Dry open places, Ohio to Wisc. and Minn., and southward.—Rays showy, 1–2´ long.