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Urtica urens

L. (1753)

This name is accepted

Kingdom: Viridiplantae Phylum: Magnoliophyta Class/Clade: Eudicot-Rosids Order: Rosales Family: Urticaceae Genus: Urtica

burning nettle, dog nettle, dwarf nettle

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Description

Key Characters:

Growth Form: Annual herb.

Stems: Stems erect or ascending with watery sap, unbranched or branched from base, 10–60(–80) cm long, glabrous or sparsely pubescent and with scattered, coarse, stinging hairs, hispidulous at nodes.

Roots: Taprooted.

Leaves: Leaves simple. Opposite. Blades elliptic to ovate, (2.5–)4–13 cm long, (0.7–)1.5–5.2 cm wide, often larger toward apex of stem. Surfaces glabrous except with scattered stinging hairs; blades thin. Margins coarsely laciniate–serrate. 3–5-veined. Petioles 0.5– 4.2 cm long. Stipules prominent, lateral, distinct or connate and interpetiolar; oblong, 1–4 mm long.

Flowers: Flowers in axillary, racemose, paniculate or loose clusters but predominantly pistillate, 0.5–2(–2.5) cm long. Flowers unisexual (and the plants monoecious or rarely dioecious). Calyx of staminate flowers deeply 4-lobed, the lobes imbricate, hispid; Calyx of pistillate flowers 4-lobed, 1.5–2.5 mm long in fruit, ± sparsely hispid, margins hispid–ciliate. Corolla (petals) absent. Stamens in staminate flower 4; filaments incurved in bud, elastically reflexed when pollen is shed; anthers dithecal, opening by longitudinal slits. Ovary superior (pistillate flowers), straight, psuedomonomerous, 1-celled; ovule 1, basal; style 1; stigma sessile or nearly so. Staminate pistillode cup-like, ovary vestigial and sterile.

Fruit: Achenes deltoid; 1.5–2.5 mm long; smooth to slightly roughened with punctate dots. Seeds 1 per achene.

Ploidy: 2n = 24; 26; 52

Habitat: Pastures and subalpine forest.

Elevation Range: 790–2290 m.

Historical Distribution

Images

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Uses and Culture

USES

Natural History

Statewide Status

Naturalized

Island Status

O'ahu Naturalized
Hawai'i Naturalized

Dispersal Agents

Forestry

Pollinators

Notes

  • 790-2290 m
  • Description digitized by Alyssa Larson
  • Description digitized from the Manual of the Flowering Plants of Hawaii
  • in 1909

Bibliography

Name Published In: Sp. Pl.: 984 (1753)

Other References

Wagner et al. 1990:1314 (H); Herbarium Pacificum Staff 1996:7 (O); Kevin Faccenda pers. obs. (O†, 1995)

Occurrences

SNo. Scientific Name Locality Habitat Basis of Record Description Recorded By Record Number Island Source Date
1 Urtica urens Puu Laau. Growing near hunter's cabin Preserved_Specimen Weed. Herbst, D.R. 5183 Hawaii BISH 1975-01-18
2 Urtica urens Puu Heewai cinder cone, South Kohala District Growing in rock pile at base of gully in Dodonaea eriocarpa, Pennisetum setaceum - Rhynchelytrum repens scrub grassland. Preserved_Specimen Herb. Flowers green, inconspicuous. Plant covered with stinging hairs. Cuddihy, L.W. 944 Hawaii BISH 1981-12-03
3 Urtica urens Mauna Kea; Upper Paaauhau, Pali Hooukapapa Occasional, in pasture. Localized. Preserved_Specimen Hosaka, E.Y. 1585 Hawaii BISH 1936-09-08
4 Urtica urens Puu Kapele Crater of cinder cone, ash soil. Preserved_Specimen 1 ft high. Fagerlund, G.O. 520 Hawaii BISH 1943-04-14
5 Urtica urens Kamuela Preserved_Specimen 2 ft high. Ewart III, G.R. 302 Hawaii BISH 1934-02-10
6 Urtica urens S. Kohala; Waimea, Puukapu, Pookonaka paddock Preserved_Specimen Common. 6-18 tall, branching lvs w/fine needle-like hairs. Hosaka, E.Y. 2137 Hawaii BISH 1938-06-02
7 Urtica urens Near Pohakuloa, Puu Omaokoili Preserved_Specimen Kosaka, E. 3 Hawaii BISH 1962-04-03
8 Urtica urens Hamakua District; Pohakuloa Training area, along the Saddle Road between 30 mile & 45 mile markers, within 60 ft. of road Preserved_Specimen Funk, E.J. 23 Hawaii BISH 1990-12-13
9 Urtica urens Along Saddle Road; 8.9 mi from jct. Hawaii Belt Rd. (Hwy. 190) Preserved_Specimen Wagner, W.L. 5571 Hawaii BISH 1985-06-25
10 Urtica urens Puuohu Preserved_Specimen Rock, J.F.C. 3167 Hawaii BISH 1909-06-24
11 Urtica urens Kamuela Preserved_Specimen Yamayoshi, H. Hawaii BISH 1945-01-19
12 Urtica urens Kamuela Preserved_Specimen Yamayoshi, H. Hawaii BISH 1945-01-19
13 Urtica urens Puu Heewai cinder cone, South Kohala District Growing in rock pile at base of gully in Dodonaea eriocarpa, Pennisetum setaceum - Rhynchelytrum repens scrub grassland. Preserved_Specimen Herb. Flowers green, inconspicuous. Plant covered with stinging hairs. Cuddihy, L.W. 944 Hawaii BISH 1981-12-03
14 Urtica urens Western slope of Mauna Kea, west of Puu Laau Open Sophora/Myoporum forest. Common in open understory in deep soil at bases of Myoporum trees. Preserved_Specimen Upright stinging herb up to 1.5 ft. tall. Imada, C. 200019 Hawaii BISH 2000-09-24
15 Urtica urens Mauna Loa Forest & Game Reserve; Pohakuloa Training Area, along military Kona Hwy In cinder & powdery soil in shade of Myoporum w/Dodonaea-Myoporum-Pennisetum-Sophora assoc. Preserved_Specimen Herb 20 cm high. Nagata, K.M. 1705 Hawaii BISH 1978-07-16
16 Urtica urens Mauna Kea; Kaohe Game Management Area, below large fenced exclosure at Puu Laau Large patch 10 x 15 ft. beneath naio trees. Numerous seedlings. Frequently seen herb. Preserved_Specimen Davis, J. 703 Hawaii BISH 1982-02-26
17 Urtica urens Along access road to Nuanuu Pali State Park above highway (tunnel) Roots at nodes in water. Preserved_Specimen 9' x 12' patch. Stings upon contact. Hong, M. Oahu BISH 1995-05-16
18 Urtica urens Hale Pohaku, Mauna Kea, Hamakua District Growing beneath mamane tree near road in open mamane parkland. Preserved_Specimen Small herb. Flowers small, green. Cuddihy, L.W. 890 Hawaii BISH 1981-10-06
19 Urtica urens Puuohu. Near the dairy & also found plentiful at & near the stone wall of Mana house. (Parker Ranch) Growing w/cultivated plants. Preserved_Specimen Rock, J.F.C. 3169 Hawaii BISH 1909-06-24
20 Urtica urens Mauna Kea, near Puu Laau Cabin Growing w/Hesperocnide under a Sophora tree in sandalwood enclosure. Preserved_Specimen Herbst, D.R. 5943 Hawaii BISH 1977-07-06
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