39. Hypericum mutilum Linnaeus, Sp. Pl. 2: 787. 1753.
Dwarf St. John’s wort Dwarf St. John’s wort
Sarothra mutila (Linnaeus) Y. Kimura
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.
Subspecies 2 (2 in the flora): c, e North America; introduced in w North America.