Hypericum gymnanthum Engelm. & A.Gray

Herbs annual, usually erect, sometimes shortly decumbent and rooting, basal branches none, rarely with 1–3(–6) pairs of narrowly ascending branches distally, 0.6–7 dm. Stems: internodes 4-angled. Leaves spreading, sessile or amplexicaul; blade usually ovate-triangular to broadly ovate, rarely oblong (mid and distal blades lanceolate-deltate), 5–25 × 3–12 mm, papery to membranous, margins plane, apex usually subacute, basal veins (3–)5, midrib usually with 1–2 pairs of branches. Inflorescences laxly corymbiform to cylindric, (1–)5–65-flowered, branching mostly dichasial. Flowers 4.5–7 mm diam.; sepals lanceolate to narrowly ovate, equal, 3–5 × 0.8–1.2 mm, <margins sometimes ciliate, not setulose-ciliate>, apex acute to acuminate; petals bright yellow, oblanceolate, 2–4 mm; stamens 10–14, scarcely grouped; styles 0.5–0.7 mm; stigmas broadly capitate. Capsules narrowly conic-ellipsoid, 3–5 × 1.5–2 mm, <usually broadest at or near middle>. Seeds 0.5–0.6 mm; testa finely linear-scalariform. 2n = 16.