Jepson eFlora: Taxon page
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Hypericum perforatum subsp. perforatum
KLAMATHWEED

Higher Taxonomy
Family: HypericaceaeView Description 

Common Name: ST. JOHN'S WORT FAMILY
Habit: Annual to shrub [tree]. Leaf: cauline, simple, opposite or whorled, often gland-dotted; stipules 0. Inflorescence: cyme, panicle, or flower 1, 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[5], placentas generally axile, style branches 3. Fruit: capsule, generally septicidal. Seed: many, small.
Genera In Family: 37 genera, 1610 species: worldwide, largely tropics. Note: Sometimes included in Clusiaceae.
eFlora Treatment Author: Robert E. Preston & Jennifer Talbot
Scientific Editor: Douglas H. Goldman, Bruce G. Baldwin.
Genus: HypericumView DescriptionDichotomous Key

Habit: Annual to shrub, glabrous. Leaf: sessile Inflorescence: generally terminal cymes, bracted. Flower: sepals [4]5; petals [4]5, deciduous or persistent, generally +- yellow; anthers occasionally black-dotted; ovary chambers 1 or 3(5), placentas 3(5), axile or parietal, projecting into chamber.
Species In Genus: +- 450 species: worldwide. Etymology: (Greek name)

Hypericum perforatum L. subsp. perforatum
NATURALIZED
Habit: Perennial herb 3--12 dm, taprooted. Stem: erect, many from base; sterile axillary branches generally 2--10 cm. Leaf: 1.5--2.5 cm, narrowly 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, black- and clear-dotted; petals 8--12 mm, +- oblong, densely black-gland-dotted, bright yellow, twisting, drying in age; stamens in 3 clusters, anthers black-dotted; styles 4--6 mm. Fruit: 7--8 mm, unlobed. Seed: +- 1 mm, brown.
Ecology: Open, disturbed areas in many plant communities; Elevation: 6--1980 m. Bioregional Distribution: NW, CaR, n&c SN, ScV (uncommon s SN, CW, PR, MP); Distribution Outside California: to eastern North America; native to Europe. Toxicity: TOXIC to livestock. Flowering Time: May--Aug Note: 3 other subspecies in Europe, Asia.
Unabridged Note: Antibiotic, antidepressant properties. Compound hypericin inhibits HIV.
eFlora Treatment Author: Robert E. Preston & Jennifer Talbot
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Noxious Weed

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botanical illustration including Hypericum perforatum subsp. perforatum

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Citation for this treatment: Robert E. Preston & Jennifer Talbot 2016. Hypericum perforatum subsp. perforatum, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=91766, accessed on August 24, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on August 24, 2016.


Geographic subdivisions for Hypericum perforatum subsp. perforatum:
NW, CaR, n&c SN, ScV (uncommon s SN, CW, PR, MP);
Markers link to CCH specimen records. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues. Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
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map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).

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Data provided by the participants of the Consortium of California Herbaria.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.