Hypericum perforatum L. - St. John's Wort
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).
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.
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.
|