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Common name: Pale Knotweed
Persicaria lapathifolia (L.) Delarbre APNI*
Synonyms: Polygonum lapathifolium L. APNI*
Polygonum lanigerum R.Br. APNI*
Description: Plant erect to ascending, 50–180 cm high, usually glabrous; sometimes rooting at nodes, often reddish, often with scattered sessile glands.
Leaves ovate to narrow-elliptic, 6–21 cm long, 10–45 mm wide, with glands dense on lower surface and scattered on upper; veins and margins pubescent, occasionally tomentose; petiole 5–22 mm long; ocrea without cilia.
Spikes elongate-cylindrical, dense, 2.5–6 cm long, 4–7 mm diam., with flowers crowded and overlapping. Perianth segments 1.5–2.7 mm long.
Achene lenticular, 1.5–2.0 mm long, 1.2–1.7 mm diam., brown to dark brown.
Distribution and occurrence: Widespread over the State and in other States. Generally in habitats favoured by pioneer species and introduced species, so its status is not clear, but here regarded as probably native. Regarded by Timson (1963) as native to Europe and Asia.
In at least seasonally damp, open situations such as beside streams and roadside ditches.
NSW subdivisions: NC, CC, SC, NT, CT, ST, NWS, CWS, SWS, NWP, SWP, NFWP, SFWP
Other Australian states: Qld Vic. Tas. S.A. N.T.
A variable species, as discussed by J. Timson ( Watsonia 5: 386-395 (1963), that seems to consist of several strains maintained by inbreeding - the pattern may be confused by weedy spread now. Plants with very woolly leaves have been distinguished in the past but this seems to be a sporadic variant not worth recognition - the same plant may bear both woolly and non-woolly leaves, or leaves may be woolly on only the abaxial surface.
Text by K. L. Wilson (1990); edited KL Wilson (Jan 2014)
Taxon concept: Flora of NSW 1 (1990)
APNI* Provides a link to the Australian Plant Name Index (hosted by the Australian National Botanic Gardens) for comprehensive bibliographic data
***The AVH map option provides a detailed interactive Australia wide distribution map drawn from collections held by all major Australian herbaria participating in the Australian Virtual Herbarium project.