Jepson eFlora: Taxon page
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Urtica urens

Higher Taxonomy
Family: UrticaceaeView DescriptionDichotomous Key

Habit: Annual, perennial herb [to shrub, soft-wooded tree], hairs stinging and not [glabrous]; monoecious or dioecious; wind-pollinated. Leaf: alternate or opposite, generally stipuled, petioled, blade often with translucent, raised dots due to crystals in epidermal cells. Inflorescence: axillary, 1-flowered or head-, raceme-, or panicle-like. Flower: generally unisexual, small, +- green; sepals generally 4--5, free to fused; petals 0. Staminate Flower: stamens generally 4--5, opposite sepals, incurved in bud, reflexing suddenly when flower opens. Pistillate Flower: ovary 1, superior, chamber 1, style 0--1, stigma 1, generally hair-tufted. Fruit: generally achene.
Genera In Family: 50 genera, 700 species: worldwide; some cultivated (Boehmeria, ramie; Pilea, clearweed).
eFlora Treatment Author: Robert E. Preston & Dennis W. Woodland
Scientific Editor: Thomas J. Rosatti.
Genus: UrticaView DescriptionDichotomous Key

Habit: Annual, perennial herb [to shrub], weak, stinging hairs 0 or few to many; monoecious or dioecious. Stem: branched or not, erect, spreading, or decumbent. Leaf: opposite, lanceolate to cordate, toothed, prominently 3--5-veined from base; crystals round to elongate. Inflorescence: head-, raceme-, or panicle-like. Staminate Flower: sepals 4, +- free, green, sharp-bristly; stamens 4. Pistillate Flower: sepals 4, +- free, outer 2 < inner 2. Fruit: lenticular to deltate, enclosed by 2 inner sepals.
Species In Genus: +- 45 species: especially temperate. Etymology: (Latin: to burn, from stinging hairs)

Urtica urens L.
Habit: Annual 1--6(8) dm, from slender taproot, monoecious; non-stinging hairs 0 to moderate. Stem: simple or branched, erect. Leaf: blade 18--40(90) mm, elliptic to broad-elliptic, base wedge-shaped, margins coarse-serrate, tip acute. Inflorescence: generally head- or spike-like, 5--25 mm, often < petiole, of staminate and pistillate flowers. Fruit: 1.5--2.5 mm, deltate. Chromosomes: 2n=24,26,52.
Ecology: Disturbed areas, stream banks, shaded areas in grassland, oak woodland, chaparral, coastal-sage scrub, riparian woodland; Elevation: < 1000 m. Bioregional Distribution: NCo, NCoRO, n&s SNF, Teh, GV, CW, SW, w DSon (Coachella Valley), reported from MP; Distribution Outside California: native to Europe. Flowering Time: Jan--Jun
eFlora Treatment Author: Robert E. Preston & Dennis W. Woodland
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Previous taxon: Urtica dioica subsp. holosericea
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botanical illustration including Urtica urens


Citation for this treatment: Robert E. Preston & Dennis W. Woodland 2017. Urtica urens, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on October 19, 2017.

Citation for the whole project: Jepson Flora Project (eds.) 2017. Jepson eFlora,, accessed on October 19, 2017.

Urtica urens
click for enlargement
© 2009 Neal Kramer
Urtica urens
click for enlargement
© 2005 Keir Morse
Urtica urens
click for enlargement
© 2009 Neal Kramer
Urtica urens
click for enlargement
© 2016 Keir Morse

More photos of Urtica urens in CalPhotos

Geographic subdivisions for Urtica urens:
NCo, NCoRO, n&s SNF, Teh, GV, CW, SW, w DSon (Coachella Valley), reported from 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.
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).

View elevation by latitude chart
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.