Jepson Flora Project: Jepson Interchange    

 
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Jepson Interchange (more information)
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HYPERICACEAE

ST. JOHN'S WORT FAMILY

Jennifer Talbot

Annual, perennial herb, shrub, tree
Leaves simple, cauline, opposite or whorled; stipules 0; blade often with black dots or embedded clear glands
Inflorescence: cyme, panicle, or flower solitary, terminal or axillary
Flower bisexual, radial; sepals persistent, generally 5, often fused at base, overlapping; petals generally 5, free; stamens generally many, free or ± fused into 3–5 clusters; pistil 1, ovary superior, chambers 1–3, placentas generally axile, style branches 3
Fruit: capsule, generally septicidal
Seeds many, small
Genera in family: 10 genera, 400 species: worldwide.

HYPERICUM

Annual, perennial herb, shrub, glabrous
Leaf sessile, ± gland-dotted
Inflorescence: generally cyme, generally terminal, bracted
Flower: sepals 5; petals 5, deciduous or persistent, yellow; anthers sometimes black-dotted; ovary chambers 1 or 3, placentas 3, axile or parietal and projecting into chamber
Species in genus: 350 species: worldwide
Etymology: (Greek name)

Introduced

H. perforatum L.

KLAMATHWEED

Perennial from taproot
Stems erect, many from base, 3–12 dm; sterile axillary branches generally 2–10 cm
Leaf 1.5–2.5 cm, linear to oblong; margins rolled under, black-dotted; lower surface conspicuously clear-dotted
Inflorescence: flowers generally 25–100 per stem
Flower: sepals 4–5 mm, lanceolate, acuminate, with black and clear dots, margin glabrous; petal 8–12 mm, ± oblong, copiously black gland-dotted, twisting after flower, bright yellow; stamens many, in 3 clusters, anthers black-dotted; styles 4–6 mm
Fruit 7–8 mm, unlobed
Seed ± 1 mm, brown
Ecology: Pastures, abandoned fields, disturbed places
Elevation: < 1500 m.
Bioregional distribution: Northwestern California, High Cascade Range, n&c Sierra Nevada, Sacramento Valley, Central Coast, San Francisco Bay Area, Peninsular Ranges
Distribution outside California: to eastern N.America, native to Europe
May produce seed without fertilization. Seriously TOXIC to livestock; the toxin hypericin inhibits human immunodeficiency virus. Weedy.

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