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garden knotweed, garden smartweed, Himalayan knotweed, Kashmir plume

heartweed, lady's-thumb, lady's-thumb smartweed, redshank, renouée persicaire, spotted lady's-thumb

Habit Plants annual, (0.5–)1–7(–13) dm; roots also often arising from proximal nodes; rhizomes and stolons absent.
Stems

procumbent, decumbent, ascending, or erect, simple or branched, without obvious ribs, glabrous or appressed-pubescent.

Leaves

ocrea light brown, cylindric, 4–10(–15) mm, chartaceous, base inflated, margins truncate, ciliate with hairs 1–3.5(–5) mm, surface glabrous or strigose, rarely with spreading hairs, not glandular-punctate;

petiole 0.1–0.8 cm, glabrous or strigose, leaves sometimes sessile;

blade often with dark triangular or lunate blotch adaxially, lanceolate to narrowly ovate, (1–)5–10(–18) × (0.2–)1–2.5(–4) cm, base tapered or cuneate, margins antrorsely strigose, apex acute to acuminate, faces glabrous or strigose, especially along midveins, sometimes glandular-punctate abaxially.

Inflorescences

terminal and axillary, erect, usually uninterrupted, 10–45(–60) × 7–12 mm;

peduncle 10–50 mm, glabrous or, rarely, pubescent;

ocreolae overlapping or sometimes interrupted proximally, margins ciliate with bristles 0.2–1.3(–2) mm.

Pedicels

ascending, 1–2.5 mm.

Flowers

4–14 per ocreate fascicle, homostylous;

perianth greenish white proximally and roseate distally or entirely roseate, not glandular-punctate, scarcely accrescent;

tepals 4–5, connate ca. 1/3 their length, obovate, 2–3.5 mm, veins prominent, not anchor-shaped, margins entire, apex obtuse to rounded;

stamens 4–8, included;

anthers yellow or pink, ovate;

styles 2–3, connate proximally.

Achenes

included or apex exserted, brownish black to black, discoid or biconvex to 3-gonous, (1.9–)2–2.7 × (1.5–) 1.8–2.2 mm, shiny, smooth.

2n

= 44.

Persicaria wallichii

Persicaria maculosa

Phenology Flowering Mar–Nov.
Habitat Weedy, moist semiwaste to cultivated areas
Elevation 0-2500 m (0-8200 ft)
Distribution
from FNA
CA; MA; OR; BC; Asia
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NL; NS; ON; PE; QC; SK; YT; SPM; Africa; Greenland; Eurasia; Pacific Islands (New Zealand) [Introduced in North America]
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 2 (1 in the flora).

Persicaria wallichii is an ornamental that escapes infrequently in the flora area. A population in Nova Scotia apparently was ephemeral. Plants with leaf blades sparsely to densely pubescent abaxially and pedicels glabrous are var. wallichii, to which naturalized North American plants appear to be referable. Plants with leaf blades brownish-tomentose abaxially and pedicels usually pubescent are var. tomentosa S. P. Hong, which may be in cultivation in North America.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

An allozyme study by L. L. Consaul et al. (1991) provided evidence of the allotetraploid origin of Persicaria maculosa, with P. lapathifolium as one of the parents. Plants with stems spreading-hairy and peduncles stipitate-glandular have been named P. maculosa subsp. hirsuticaulis (Danser) S. Ekman & Knutsson. Material referable to this subspecies has not been seen among North American specimens. Hybrids between P. maculosa and P. minor have been documented in Europe (R. H. Roberts 1977).

The Cherokee, Chippewa, and Iroquois prepared simple or compound decoctions of Persicaria maculosa, which they used as dermatological, urinary, gastrointestinal, and veterinary aids, for heart medicine, and as an analgesic (D. E. Moerman 1998).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 5, p. 581. FNA vol. 5, p. 593.
Parent taxa Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Rubrivena Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Persicaria
Sibling taxa
P. amphibia, P. arifolia, P. bicornis, P. bungeana, P. capitata, P. careyi, P. chinensis, P. glabra, P. hirsuta, P. hydropiper, P. hydropiperoides, P. lapathifolia, P. longiseta, P. maculosa, P. meisneriana, P. minor, P. nepalensis, P. orientalis, P. pensylvanica, P. perfoliata, P. punctata, P. robustior, P. sagittata, P. setacea, P. virginiana
P. amphibia, P. arifolia, P. bicornis, P. bungeana, P. capitata, P. careyi, P. chinensis, P. glabra, P. hirsuta, P. hydropiper, P. hydropiperoides, P. lapathifolia, P. longiseta, P. meisneriana, P. minor, P. nepalensis, P. orientalis, P. pensylvanica, P. perfoliata, P. punctata, P. robustior, P. sagittata, P. setacea, P. virginiana, P. wallichii
Subordinate taxa
P. wallichii var. wallichii
Synonyms Polygonum polystachyum, Aconogonon polystachyum, Pleuropteropyrum polystachyum, Reynoutria polystachya, Rubrivena polystachya Polygonum persicaria, P. fusiformis, P. vulgaris, Polygonum fusiforme, Polygonum persicaria var. ruderale, Polygonum puritanorum
Name authority Greuter & Burdet: Willdenowia 19: 41. (1989) Gray: Nat. Arr. Brit. Pl. 2: 269. (1822)
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