Sp. Pl. 2: 804. 1753.
Plants 15–60+ cm. Stems proximally usually glabrous, sometimes piloso-hirsute and/or stellate-pubescent, distally usually glabrous, sometimes stellate-pubescent. Leaves: basal 0(–2), cauline (5–)8–15(–45+); blades lance-elliptic to lanceolate, (20–)50–100(–150) × (10–)15–25(–40+) mm, lengths (3–)5–10+ times widths, bases cuneate to rounded or truncate (then sometimes ± clasping), margins usually toothed (to laciniate), denticulate, or entire (often ± revolute, at least distally), apices obtuse to acute, faces glabrous or ± stellate-pubescent, sometimes ± scabrellous (especially at or near distal margins). Heads (1–)5–30(–100+) in corymbiform to subumbelliform arrays. Peduncles usually stellate-pubescent. Calyculi: bractlets 9–15+. Involucres campanulate to hemispheric, (8–)9–11+ mm. Phyllaries 12–21+, apices rounded to acute, abaxial faces usually glabrous, rarely piloso-hirsute and/or stipitate-glandular. Florets 30–80+; corollas yellow, 10–18 mm. Cypselae columnar, 2.5–3.5 mm; pappi of 50–60+, stramineous to sordid bristles in ± 2 series, 6–7 mm.
Phenology: Flowering (Jun–)Jul–Sep.
Habitat: Disturbed sites (fields, roadsides), rocky slopes, openings in forests, prairies, thickets
Elevation: 600–3200 m
Greenland, St. Pierre and Miquelon, Alta., B.C., Man., N.B., Nfld. and Labr., N.W.T., N.S., Ont., P.E.I., Que., Sask., Yukon, Alaska, Colo., Conn., Idaho, Ill., Ind., Iowa, Maine, Mass., Mich., Minn., Mo., Mont., Nebr., N.H., N.J., N.Y., N.Dak., Ohio, Oreg., Pa., R.I., S.Dak., Vt., Wash., W.Va., Wis., Wyo., Europe, Asia.
The circumscription of Hieracium umbellatum adopted here is supported by research done by others, especially G. A. Guppy (1978) and E. Lepage (1960). Hieracium canadense var. kalmii (Linnaeus) Scoggan, referable here, is an illegitimate name.