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arrow-leaf knotweed, arrow-leaf tearthumb, arrow-vine, renouée sagittée

Asiatic smartweed, Asiatic tearthumb, devil's-tail, devil's-tail or giant climbing tearthumb, giant climbing tearthumb, mile a minute, mile-a-minute weed

Habit Plants annual, 3–20 dm; roots also often arising from proximal nodes. Plants annual, 10–20(–70) dm; roots not also arising from proximal nodes.
Stems

scandent, ribbed, glabrous;

prickles 1–1.5 mm.

scandent, ribbed, glabrous, often glaucous;

prickles 0.5–1 mm.

Leaves

ocrea brownish, cylindric, (3–)5–13 mm, chartaceous, base inflated or not, without prickles, margins oblique, glabrous or ciliate at tip with bristles 0.2–1 mm, surface glabrous;

petiole 0.5–4 cm;

blade broadly lanceolate to oblong, 2–8.5 × 1–3 cm, base sagittate to cordate, margins entire, ciliate or eciliate, apex obtuse to acute, faces glabrous or densely appressed-pubescent, usually with retrorse prickles along midvein abaxially.

ocrea green, plane to broadly funnelform, 9–14 mm, at least some foliaceous, base inflated or not, without prickles, margins oblique, eciliate, surface glabrous, glaucous;

petiole 4.5–8 cm;

blade triangular, 4–7 × 4.5–9 cm, base truncate to cordate, usually peltate, margins entire, sparsely retrorsely prickly, apex acuminate, faces glabrous, usually glaucous abaxially.

Inflorescences

capitate or paniclelike, uninterrupted, 5–15 × 4–10 mm;

peduncle 10–80 mm, usually glabrous, sometimes with retrorse prickles proximally;

ocreolae overlapping, margins eciliate.

capitate or spikelike, uninterrupted, 5–12 × 5–10 mm;

peduncle 10–50 mm, retrorsely prickly;

ocreolae overlapping, margins eciliate.

Pedicels

mostly ascending, 1–1.5 mm.

mostly ascending, 1–3 mm.

Flowers

2–3 per ocreate fascicle;

perianth white or greenish white, often tinged pink or red, sometimes entirely pink, glabrous, accrescent, not becoming blue and fleshy in fruit;

tepals 5, connate 1/3–1/2 their length, broadly elliptic, 3–5 mm, apex obtuse;

stamens 8, filaments distinct, free;

anthers pink, ovate;

styles 3, connate to middle.

1–3 per ocreate fascicle;

perianth greenish white, glabrous, accrescent, becoming fleshy and blue in fruit;

tepals 5, connate to ca. 1/3 their length, broadly elliptic, 2–3.5 mm, apex acute to obtuse;

stamens (6–)8, filaments distinct, free;

anthers pinkish, ovate;

styles 3, connate proximally.

Achenes

included or styles exserted, light or dark brown to black, 3-gonous, 2.5–4 × 1.8–2.5 mm, dull to shiny, smooth to minutely punctate.

included, black or reddish black, spheroidal, 3–3.5 × 3–3.5 mm, shiny, smooth.

2n

= 40.

Persicaria sagittata

Persicaria perfoliata

Phenology Flowering Jun–Oct. Flowering Jun–Oct.
Habitat Moist shaded sites, meadows, pastures, fens, swamps, shorelines of ponds and streams Thickets, streams banks, pastures, forest edges, roadsides, railroad embankments, other moist, disturbed sites
Elevation 0-1000 m (0-3300 ft) 0-300 m (0-1000 ft)
Distribution
from FNA
AL; AR; CO; CT; DC; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; ND; NE; NH; NJ; NY; OH; OK; PA; RI; SC; SD; TN; TX; VA; VT; WI; WV; MB; NB; NF; NS; ON; PE; QC; e Asia
[WildflowerSearch map]
[BONAP county map]
from FNA
CT; DC; DE; MD; MS; NJ; NY; OH; OR; PA; RI; VA; WV; Asia [Introduced in North America]
[WildflowerSearch map]
[BONAP county map]
Discussion

Persicaria sagittata is an extremely variable species. Achene and leaf characters have been used by some authors to separate North American and Asian populations, but these characters show weak geographic variation (C. W. Park 1988).

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

Persicaria perfoliata is an aggressive, fast-growing pest in its native range and in North America. At least some introductions appear to be through the nursery trade (J. C. Hickman and C. S. Hickman 1978; R. E. Riefener 1982). It was collected once in 1954 in British Columbia, but that population did not persist.

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

Source FNA vol. 5, p. 577. FNA vol. 5, p. 577.
Parent taxa Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Echinocaulon Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Echinocaulon
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. setacea, P. virginiana, P. wallichii
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. punctata, P. robustior, P. sagittata, P. setacea, P. virginiana, P. wallichii
Synonyms Polygonum sagittatum, Polygonum sagittatum var. gracilentum, Tracaulon sagittatum, Truellum sagittatum Polygonum arifolium var. perfoliatum, Polygonum perfoliatum
Name authority (Linnaeus) H. Gross: Beih. Bot. Centralbl. 37(2): 113. (1919) (Linnaeus) H. Gross: Beih. Bot. Centralbl. 37(2): 113. (1919)
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