Jepson eFlora: Taxon page
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Urtica dioica

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 dioica L.
Habit: Perennial herb 5--30 dm, from rhizome, +- erect, stinging hairs few to many, non-stinging 0 to dense, generally shorter. Leaf: blade 6--20 cm, narrow-lanceolate to wide-ovate, base tapered to cordate. Inflorescence: spike-, raceme-, or panicle-like, 1--7 cm, generally > petiole, of staminate or pistillate flowers. Fruit: ovate.
Note: Urtica dioica subsp. dioica dioecious, native to Eurasia; naturalized in North America; report from California in FNANM based on an unconfirmed collection.
eFlora Treatment Author: Robert E. Preston & Dennis W. Woodland
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Citation for this treatment: Robert E. Preston & Dennis W. Woodland 2016. Urtica dioica, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on October 27, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora,, accessed on October 27, 2016.

Urtica dioica subsp. holosericea
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© 2013 Neal Kramer
Urtica dioica subsp. holosericea
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© 2009 Keir Morse
Urtica dioica subsp. gracilis
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© 2016 Keir Morse
Urtica dioica subsp. holosericea
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© 2013 Neal Kramer
Urtica dioica subsp. holosericea
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© 2006 Steve Matson
Urtica dioica subsp. holosericea
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© 2007 Neal Kramer

More photos of Urtica dioica in CalPhotos

Geographic subdivisions for Urtica dioica:
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).

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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.