Polygonum strigosum R.Br.
Vascular – Exotic
Herbs - Dicotyledons other than Composites
The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.
Prickly scrambling herb, either forming dense patches or scrambling through other vegetation, leaves mostly triangular in outline with backward pointing lobes, small (2 to 3 mm long) pink flowers in open branched flowerheads at the top of stem.
Northland to northern Waikato.
Swamp and water body margins.
Wetland plant indicator status rating
FACW: Facultative Wetland
Usually is a hydrophyte but occasionally found in uplands (non-wetlands).
Annual herb; stems to > 50 cm long, lax or sprawling, with numerous deflexed scabrid bristles to c. 1 mm long; roots slender. Lvs ± similar; petiole to 1 cm long, filiform, scabrid. Lamina 3-7 × 0.5-1.2 cm, linear-lanceolate; midrib below with scattered bristles; margin ciliolate, entire; base ± hastate or sagittate; apex obtuse or subacute. Ochreae usually 1-1.5 cm long, glabrous, soon brown and papery; apex truncate. Racemes terminal or in axils of upper lvs, to 12 cm long, very slender; fls few, distant. Peduncles dichotomous, conspicuously glandular-hairy, > lvs; pedicels very short, hidden by sheathing, glabrous or glabrate bracts until after anthesis. Perianth 2-3 mm long, accrescent, pink; segments ± broadly ovate-elliptic, imbricate and remaining almost closed, eglandular. Nut 2-2.5 mm long (including short beak), broad-ovoid or ellipsoid, brown, shining.
Unlike any other willow weed, with prickly stems and leaves and the sprawling growth habit.
January to February
Seed dispersed by water, animals or contaminated machinery.
Reason for introduction
Unknown, seed or soil contaminant.
Not controlled in New Zealand.
persicaria: Medieval name referring to the likeness of the leaves to a peach tree
Prepared by Paul Champion and Deborah Hofstra (NIWA). Features description from Webb et al. (1988).
References and further reading
Johnson PN, Brooke PA (1989). Wetland plants in New Zealand. DSIR Field Guide, DSIR Publishing, Wellington. 319pp.
Webb, C.J.; Sykes, W.R.; Garnock-Jones, P.J. (1988). Flora of New Zealand Volume 4: Naturalised pteridophytes, gymnosperms, dicotyledons. Botany Division, DSIR, Christchurch.