Burke: Hypericum perforatum vs. Hypericum canadense

	Hypericum perforatum	Hypericum canadense
	common St. John's-wort, Klamath weed	Canadian St. John's-wort
Habit	Taprooted perennial with short rhizomes, the stems erect, 1-several, freely-branched, 3-8 dm. tall.
Leaves	Leaves opposite, sessile, narrowly spatulate-oblanceolate to lanceolate, 1-3 cm. long, dotted with purplish-black, not clasping, but connected by narrow, wing-like structures at the base.
Flowers	Inflorescence of large, many-flowered, leafy-bracteate, compound cymes; sepals 5, lanceolate, acute, 5-7 mm. long; petals 5, yellow, about twice as long as the sepals, their margins with conspicuous, black spots; stamens 75-100, attached at the base into 3 distinct groups; styles 3.
Fruits	Capsule 5-8 mm. long, 3-celled, acute.

	Hypericum perforatum	Hypericum canadense
Flowering time	June-July	July-September
Habitat	Noxious weed of fields, meadows, roadsides, forest edge, wastelots, and other disturbed areas from the lowlands to near subalpine.	Coastal, shores, damp sand or peat, damp or wet disturbed ground, and cranberry farms.
Distribution	Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast. [WildflowerSearch map] [BONAP county map]	Occurring west of the Cascades crest in Washington; southwestern British Columbia to southwestern Oregon. [WildflowerSearch map] [BONAP county map]
Origin	Introduced from Europe	Introduced from eastern North America
Conservation status	Not of concern	Not of concern
Sibling taxa	H. anagalloides, H. androsaemum, H. boreale, H. calycinum, H. canadense, H. ellipticum, H. maculatum, H. majus, H. mutilum, H. scouleri, H. tetrapterum	H. anagalloides, H. androsaemum, H. boreale, H. calycinum, H. ellipticum, H. maculatum, H. majus, H. mutilum, H. perforatum, H. scouleri, H. tetrapterum
Subordinate taxa	H. perforatum ssp. perforatum
Web links	Local floras: BC, OR, WA Local Web sites: Flora NW, PNW Herbaria, Turner Photog. WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local floras: OR, WA Local Web sites: Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Hypericum perforatum

Hypericum canadense

common St. John's-wort, Klamath weed

Canadian St. John's-wort

Habit

Taprooted perennial with short rhizomes, the stems erect, 1-several, freely-branched, 3-8 dm. tall.

Leaves

Leaves opposite, sessile, narrowly spatulate-oblanceolate to lanceolate, 1-3 cm. long, dotted with purplish-black, not clasping, but connected by narrow, wing-like structures at the base.

Flowers

Inflorescence of large, many-flowered, leafy-bracteate, compound cymes;

sepals 5, lanceolate, acute, 5-7 mm. long;

petals 5, yellow, about twice as long as the sepals, their margins with conspicuous, black spots;

stamens 75-100, attached at the base into 3 distinct groups;

styles 3.

Fruits

Capsule 5-8 mm. long, 3-celled, acute.