Herbs annual, erect, branches strict, in distal 1/2, 1–8 dm, wiry. Stems: internodes 4-lined. Leaves erect to suberect, sessile; blade linear or linear-subulate to linear-lanceolate, 5–22 × 0.5–1 mm, subcoriaceous, margins recurved to revolute, apex acute to obtuse, basal vein 1, midrib unbranched. Inflorescences narrowly to broadly triangular, 1–12-flowered, branching mostly monochasial. Flowers 5–8 mm diam.; sepals narrowly oblong to linear-lanceolate, subequal, 3–7 × 0.7–1.3 mm, apex acute; petals golden yellow to orange-yellow, oblong, 4–7 mm; stamens 10–22, separate or obscurely 3-fascicled; styles (0.5–)0.8–1.5 mm; stigmas broadly capitate. Capsules narrowly ovoid to ovoid-cylindric, 3.5–7 × 2.5–3 mm, length 1–1.2 times sepals. Seeds 0.9–1.1 mm; testa finely scalariform. 2n = 24.
Phenology: Flowering summer–early fall (Jul–Sep).
Habitat: Dry, sandy or clay soil in open woods, old fields, waste or rocky places
Elevation: 0–1100 m
Ala., Ark., Fla., Ga., Ill., Ind., Iowa, Kans., Ky., La., Miss., Mo., N.C., Ohio, Okla., S.C., Tenn., Tex., Va.
Hypericum drummondii is closely related to H. gentianoides.