Sp. Pl. 2: 787. 1753.
Herbs annual or perennial, usually erect, sometimes decumbent and rooting, basal branches sometimes present, usually with to 10 pairs of spreading branches distal to middle, 0.5–8 dm. Stems: internodes 4-angled. Leaves spreading, sessile or amplexicaul; blade paler abaxially, ovate, elliptic, or elliptic-oblong (proximal), ovate or suborbiculate to elliptic or lanceolate (mid and distal), 3–27(–40) × 1–15 mm, papery to membranous, margins plane, apex obtuse to rounded, basal veins 3–5, midrib with to 3 pairs of branches. Inflorescences cylindric, 5–60-flowered, branching mostly dichasial; bracts linear-subulate. Flowers 3–5 mm diam.; sepals lanceolate to linear-lanceolate or elliptic-oblong to oblanceolate, equal or unequal, 2–4.5 × 0.6–1.5 mm, margins sometimes ciliate, not setulose-ciliate, apex usually acute to apiculate, sometimes obtuse to rounded; petals pale yellow, oblong, 1.7–3.5 mm; stamens 5–16, scarcely grouped; styles 0.5 mm; stigmas broadly capitate. Capsules narrowly ovoid to cylindric-ellipsoid, 2–5 × 1.6–2.4 mm, usually broadest at or near middle. Seeds 0.4–0.7 mm; testa finely linear-scalariform.
B.C., N.B., N.S., Ont., Que., Sask., Ala., Ark., Calif., Colo., Conn., D.C., Del., Fla., Ga., Ill., Ind., Iowa, Kans., Ky., La., Maine, Mass., Md., Mich., Miss., Mo., N.C., N.H., N.J., N.Y., Nebr., Ohio, Okla., Oreg., Pa., R.I., S.C., Tenn., Tex., Utah, Va., Vt., W.Va., Wash., Wis., introduced in w North America.
Subspecies 2 (2 in the flora).
|1||Stems: apical internode shorter than adjacent one or almost absent; inflorescences: branching mostly dichasial from 2–10 nodes.||Hypericum mutilum subsp. mutilum|
|1||Stems: apical internode usually longer than adjacent one; inflorescences: branching from 1–4(–6) nodes, branches diffuse and repeatedly monochasial distally.||Hypericum mutilum subsp. latisepalum|