Urtica L.

Volume IV (1988) - Flora of New Zealand Naturalised Pteridophytes, Gymnosperms, Dicotyledons

URTICA L.

Annual or perennial, monoecious or dioecious herbs or shrubs, usually with stinging hairs. Lvs opposite, toothed, stipulate. Infl. axillary, usually spike-like with clustered cymes, ebracteolate. Perianth green, 4-partite, not connate at base; ♀ fls with ± unequal perianth segments, the 2 larger enclosing achene; ♂ fls with 4 equal segments.

Key

All racemes with ♂ and ♀ fls; margins of perianth segments ciliate in ♀ fls

2. *urens

All racemes unisexual (rarely with a few fls of the opposite sex); margins of perianth segments glabrous or with a few irregular hairs

Basal stalk of stinging hairs much > tapered stinging translucent tip; woody shrub

5. ferox

Basal stalk of stinging hairs much < tip; annual or perennial herbs, sometimes somewhat woody at base

Rhizomatous herb

1. *dioica

Plants not rhizomatous, sometimes branches rooting at nodes

Stipules 2 per node, entire; ♂ racemes inflated

*membranacea ζ

Stipules 2 per node and 2-fid, or 4 per node and entire; racemes not inflated

Scrambling or climbing; lvs narrowly ovate to lanceolate

7. linearifolia

Erect or decumbent; lvs elliptic, deltate, or ovate to broadly ovate

Lvs broadly ovate, 10-20 cm long; Islets of Foveaux Strait and Fiordland, St., Ch., A., C., Ant.

4. australis

Lvs ovate to elliptic or deltoid, 3-10-(12) cm long; N., S., St.

Lvs ovate to elliptic, serrate, usually densely clothed in stinging hairs; dioecious

3. aspersa

Lvs ovate to deltoid, coarsely serrate to dentate, sparsely to moderately clothed in stinging hairs; monoecious

6. incisa

50 spp., mostly N. temperate, few tropical and S. temperate. Native spp. 5, naturalised 3.

The distribution of ♂ and ♀ fls is important in identification - both types of fl. are illustrated for U. urens in Fig. 119. Most spp. have stinging hairs which vary in density, distribution over the plant, and intensity of effect (see Connor 1977). The record of Meehania urticifolia by Taylor, R. L., Weeds of Roadsides and Waste Ground in New Zealand (1981), appears to be based on an Urtica sp., possibly U. dioica or U. incisa.

Urtica L.

Key

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