Flower:

Dense clusters at the tips of stems and branches. Flowers are deep yellow, 3/8 to 5/8 inch across with 5 oval to oblong petals with blunt tips and conspicuous lines of black dots. The green sepals are similarly black dotted, about half length of the petals, oval to oblong but tapered to a point. 3 styles, often red-tipped, at the top of the round central ovary are surrounded by a spray of slender yellow stamens, many of which are also black-dotted.

Leaves and stems:

Leaves are simple, opposite and stalkless to somewhat clasping, oblong to oval elliptic, ¾ to 2¼ inches long, 3/8 to ½ inch wide, toothless, hairless, with 3 to 5 prominent veins. The tip and base are rounded or tapering to a blunt point.

New leaves heavily dotted with black glands around the edges and on the underside. Stems are multiple from the base, hairless, erect and mostly unbranched except in the flower cluster.

Fruit:

Fruit is an upright, oval to ellipsoid capsule 1/6 to ¼ inch long, reddish to deep purple.

Notes:

Spotted St. John's-wort is by and large restricted to SE Minnesota with a few scattered collections in central Minnesota as far north as Cass County. The small, densely clustered flowers with heavily black dotted petals and sepals as well as black glandular dots on the terminal leaves easily distinguishes it from all other Hypericum species found in the state. While the invasive Common St. John's-wort (H. perforatum) does have black-dotted flowers, its leaves have translucent dots rather than black.