Hypericum perforatum L. - St. John's Wort

Hypericum perforatum plant

Family - Hypericaceae

Stems - Multiple from base, from thick rhizomes, to +1m tall, dichotomously branching (branches decussate), glabrous, glaucous. Midrib of leaf decurrent on stem and with black glandular punctations.

Leaves - Opposite, decussate, sessile, lance-ovate to oblong or elliptic, entire, to +1.8cm long, +7mm broad, entire, acute to obtuse, glabrous, glaucous (mostly below), with black glandular punctations on margins and a few scattered on the leaf tissue, perforate.

Inflorescence - Terminal bracteate cymes. Pedicels to 2mm long, glabrous (or flowers sessile).

Hypericum perforatum plant

Flowers - Petals (4)5, yellow, spreading, to 1.3mm long, 6mm broad, oblong, obtuse, with black glandular punctations. Stamens many (+50), erect to spreading. Filaments yellow, 7-8mm long, glabrous. Anthers biglobose, .7mm broad. Styles 3, spreading, 6mm long, glabrous, yellow. Ovary superior, glabrous, 3.5mm long, 2.1mm in diameter, ovoid, 3-locular, ovules (seeds) many. Sepals 5, linear, 5-6mm long, 1.1mm broad, acuminate, glabrous, with perforations adjacent and parallel to midrib.

Hypericum perforatum flower

Flowering - May - September.

Habitat - Pastures, fields, waste ground, roadsides, railroads.

Origin - Native to Europe.

Other info. - Feeling depressed? Chew on this. Not! Seriously though, this is the species known commonly as "St. John's Wort", which has recently been over-used as an herbal remedy for the symptoms of depression. Traditionally the plant was used as an antibacterial, an anti-inflammatory, and a host of other ailments. One of the active ingredients, hypericin, causes photodermatitis in some people and animals.
The plant can be identified in the field by the transparent (pellucid) perforations on the leaves and sepals, and the black punctate glands on the leaves and stems. The punctations are not as dense as in H. punctatum Lam., which has much smaller flowers.

Photographs taken in Pictured Rocks National Seashore, MI., 7-22-02.


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