Fourpetal St. Johnswort is a perennial herb or small shrub with a woody base, growing 20–100 cm (7.9–39.4 in) tall.
Young stems are two- or four-lined, becoming two-lined or terete as they age.
The leaves are oblong to triangular-ovate, 5–35 mm (0.20–1.38 in) long, 4–15 mm (0.16–0.59 in) across, with heart-shaped, clasping bases.
The terminal flowerheads produce one to three flowers, each flower 20–30 mm (0.79–1.18 in) in diameter with 4 bright yellow petals and about 100 stamens.
It produces flowers throughout most of the year.
The capsules are three-parted.

It is distinguished from the closely related Hypericum crux-andreae by its broader leaves with clasping bases.
Their distribution overlaps in southern Georgia and northern Florida, but apparent hybrids have not been observed.
Fourpetal St. Johnswort is a perennial herb or small shrub with a woody base, growing 20–100 cm (7.9–39.4 in) tall. Young stems are two- or four-lined, becoming two-lined or terete as they age. The leaves are oblong to triangular-ovate, 5–35 mm (0.20–1.38 in) long, 4–15 mm (0.16–0.59 in) across, with heart-shaped, clasping bases. The terminal flowerheads produce one to three flowers, each flower 20–30 mm (0.79–1.18 in) in diameter with 4 bright yellow petals and about 100 stamens. It produces flowers throughout most of the year. The capsules are three-parted.
It is distinguished from the closely related Hypericum crux-andreae by its broader leaves with clasping bases. Their distribution overlaps in southern Georgia and northern Florida, but apparent hybrids have not been observed.
Hypericum tetrapetalum