Hypericum canadense, known as Canadian St. Johns-wort, lesser St. John's wort, and lesser Canadian St. Johnswort, is a flowering plant in the genus Hypericum. It is a yellow-flowering annual or perennial herb native to North America and introduced to Ireland and The Netherlands. The specific epithet canadense means "Canadian".
Description
Hypericum canadense is a perennial herb that grows in short basal offshoots that are produced in autumn. The slender stems reach 5–75 cm (2.0–29.5 in) in height and are simple or branched in their upper half. The stems are four-angled and slightly winged. The roots are fibrous and the herb lacks any rhizome or stolons. The leaves have characteristic pellucid dots and are linear to linear-oblanceolate. The leaves are rounded at their tip and narrow towards their sessile or subpetiolar base. The leaves are 1–4 cm (0.4–1.6 in) long and 1–6 mm wide. Pairs of leaves are spirally arranged but not decussate, and lower leaves become more purplish, smaller, more elliptic, and crowded due to shortening of the internodes. The leaves are one to three nerved with secondary veins weaker except near the leaf base.
The flowers are solitary or arranged in simple cymes. The cymes are naked save for the linear bracts. Branches of the inflorescence are divergent and form a somewhat corymbiform shape. The five linear-lanceolate sepals are blunt to acutish, measuring 2.5-4.5 mm long and 0.8–1 mm wide. The sepals are shortly united at their base with one being longer than the others. The five-veined yellow petals are oblong to oblanceolate and have rounded tips, measuring about as long as the sepals or shorter. The fifteen stamens are arranged in three loose fascicles. Both the filaments and anthers are yellow, the anthers being globose and about 0.25 mm wide. The ovoid, yellow pistil is 2 mm long, with indistinct carpels and one locule. The three styles are 0.25 mm long. The conical capsule is...
