Jepson Flora Project: Jepson Interchange    

link to manual TREATMENT FROM THE JEPSON MANUAL (1993) previous taxon | next taxon
Jepson Interchange (more information)
©Copyright 1993 by the Regents of the University of California
For up-to-date information about California vascular plants, visit the Jepson eFlora.



Dennis W. Woodland

Annual to (soft-wooded) trees, glabrous or stinging-hairy, monoecious or dioecious
Leaves alternate or opposite, generally stipuled, petioled, often with embedded crystals
Inflorescence various, axillary
Flowers generally unisexual, small, greenish; sepals generally 4–5, free to fused; petals 0
Staminate flower: stamens generally 4–5, opposite sepals, in bud incurved, then springing out
Pistillate flower: ovary 1, superior, chamber 1, style 0–1, stigma 1, generally hair-tufted
Fruit: generally achene (drupe)
Genera in family: 50 genera, 700 species: worldwide; some cultivated (Boehmeria ; Pilea , clearweed)
Reference: [Miller 1971 J Arnold Arb 52:40–68]



Annual to shrub, weak, stinging-hairy or not, monoecious or dioecious
Leaves 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: ± 50 species: especially temp
Etymology: (Latin: to burn, from stinging hairs)
Reference: [Woodland 1982 Syst Bot 7:282–290]


U. dioica L.

Perennial 10–30 dm, from rhizome, ± erect
Leaf: blade generally > 40 mm, narrowly lanceolate to widely ovate, base tapered to cordate
Inflorescence spike-, raceme-, or panicle-like, 1–7 cm, generally > petiole, with only staminate or pistillate flowers
Fruit ovate
Ecology: Streambanks, margins of deciduous woodlands, moist waste places
Elevation: < 3000 m.
Bioregional distribution: California Floristic Province, White and Inyo Mountains, Desert Mountains
Distribution outside California: US, Canada, n Mexico, Eurasia
Ssp. d. dioecious, native to Eurasia; naturalized in North America including CA.

previous taxon | next taxon
bioregional map for URTICA%20dioica being generated
YOU CAN HELP US make sure that our distributional information is correct and current. If you know that a plant occurs in a wild, reproducing state in a Jepson bioregion NOT highlighted on the map, please contact us with that information. Please realize that we cannot incorporate range extensions without access to a voucher specimen, which should (ultimately) be deposited in an herbarium. You can send the pressed, dried collection (with complete locality information indicated) to us (e-mail us for details) or refer us to an accessioned herbarium specimen. Non-occurrence of a plant in an indicated area is difficult to document, but we will especially value your input on those types of possible errors (see automatic conversion of distribution data to maps).

Retrieve Jepson Interchange Index to Plant Names entry for Urtica dioica
Retrieve dichotomous key for Urtica
Overlay Consortium of California Herbaria specimen data by county on this map
Show other taxa with the same California distribution | Read about bioregions | Get lists of plants in a bioregion
Return to the Jepson Interchange main page
Return to treatment index page
  • This page is no longer being maintained.

University & Jepson Herbaria Home Page |
General Information | University Herbarium | Jepson Herbarium |
Visiting the Herbaria | On-line Resources | Research |
Education | Related Sites
Copyright © by the Regents of the University of California