larger Canadian St. Johnswort

not listed

NNR - Unranked

SNR - Unranked

not listed

FACW - Facultative wetland

FACW - Facultative wetland

FACW - Facultative wetland

Larger Canadian St. Johnswort is an erect, perennial forb that rises from a horizontal, underground stem (rhizome) and fibrous roots. It can be 4″ to 24″ in height but is usually no more than 20″ tall. It spreads by producing short, leafy, above-ground, horizontal stems (stolons).

The stems are erect, slender, hairless, and leafy. They have few if any branches below the inflorescence. They are ridged below the base of each leaf. They do not have black glands.

The leaves are opposite, lance-shaped to narrowly oblong or narrowly elliptic, stalkless, and more or less pointing upward. The larger leaves are ¾″ to 1½″ long and ⅛″ to ⅜″ wide. They are broadly angled or rounded at the tip and broadly angled, rounded, or slightly heart-shaped and weakly clasping at the base. The bases of opposite pairs of leaves meet around the stem. They have 5 to 7 veins originating at the base: a prominent midvein; one prominent vein on each side of the midvein that extends in an unbroken arc to the tip; and one or two secondary veins. The outermost veins are strongly ascending at the base. The leaf blades are dotted with sunken, brownish, translucent glands. The upper and lower surfaces are hairless. The margins are untoothed.

The inflorescence is a branched cluster of few to many flowers at the end of the stem and at the ends of a few strongly ascending branches rising from leaf nodes immediately below. The terminal clusters together with the flowering branches form a compact, flat-topped or rounded array (cyme).

The flowers are small, ¼″ to ⅓″ in diameter. There are 5 sepals, 5 petals, 14 to 21 stamens, and 3 styles. The sepals are green, lance-shaped, and ⅛″ to ¼″ long. They are broadest below the middle and narrowly angled with straight sides along the tip. They are erect in bud, bent backward in flower. The petals are yellow, and 1 ⁄16″ to ⅛″ long. They shrivel and turn brown but often remain attached as the fruit develops. The stamens are not grouped. The anthers are yellow. The styles are about 1 ⁄32″ long. The stigmas are often reddish.

The fruit is a maroon, elliptical to cone-shaped, 3 ⁄16″ to 4 ⁄16″ long, 1-chambered capsule with numerous seeds. The capsule is pointed at the top.

4″ to 24″

Yellow

The small flower size helps to distinguish this from other Hypericum species.

Northern St. Johnswort (Hypericum boreale) sepals are broadest near the middle. The capsule is rounded at the top.

Moist to wet. Meadows, fields, lakeshores, streamsides, edges of wetlands, roadside ditches, disturbed sites.

June to September

Sources

2, 3, 4, 5, 7, 28, 29, 30.

Native

Scattered but common

The common name refers to the blooming period. The plant is usually in bloom on June 24, St. John’s Day.