Heads 12–many-flowered. Involucre more or less imbricated. Achenes short, oblong or columnar, striate, not beaked; pappus a single row of tawny and fragile capillary rough bristles.—Hispid or hirsute and often glandular perennials, with entire or toothed leaves, and single or panicled heads of mostly yellow flowers; summer and early autumn. (Name from ἱέραξ, a hawk.)
§ 1. Involucre not much imbricate, scarcely calyculate; achenes oblong; pappus not copious.
H. aurantìacum, L. Low, long-hirsute, above hispid and glandular, the involucral hairs dark; leaves all near the base of the simple peduncle; heads clustered; flowers deep orange to flame-color.—Roadsides and fields; N. Eng. to N. Y. (Nat. from Eu.)
H. præáltum, Vill. Glaucous, 2° high, only the base and lanceolate leaves hairy; heads in an open cyme; flowers yellow.—N. New York (Ward). (Nat. from Eu.)
§ 2. Heads large; involucre irregularly imbricated; achenes columnar; pappus copious, unequal.
H. muròrum, L. Stem scape-like, low; leaves oval or oblong, obtuse, toothed toward the subcordate base; heads few, dark-glandular.—Open woods near Brooklyn, N. Y. (Nat. from Eu.)
1. H. Canadénse, Michx. Stems simple, leafy, corymbed at the summit (1–3° high); leaves sessile, lanceolate or ovate-oblong, acute, remotely and very coarsely toothed, somewhat hairy, the uppermost slightly clasping.—Dry woods, N. Eng. to Penn., Minn., and northward.
§ 3. Heads small; involucre cylindrical, scarcely imbricated.
[*] Achenes columnar, not attenuate upward when mature; panicle not virgate.
2. H. paniculàtum, L. Stem slender, leafy, diffusely branched, hairy only below (1–3° high); leaves lanceolate, acute at both ends, slightly toothed, smooth; heads (very small) in a loose panicle, on slender and diverging pedicels, 12–20-flowered; achenes short.—Open woods; rather common.