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

halberd-leaf smartweed, halberd-leaf tearthumb, renouée à feuilles d'arum

Habit Plants annual, 3–20 dm; roots also often arising from proximal nodes. Plants annual, 2–15 dm; roots also often arising from proximal nodes.
Stems

scandent, ribbed, glabrous;

prickles 1–1.5 mm.

scandent, ribbed, glabrous;

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 tan or brownish, cylindric, 8–15 mm, chartaceous, base inflated or not, with prickles, margins oblique, ciliate with bristles 0.5–2.5 mm, surface glabrous or appressed- to spreading-pubescent;

petiole 1–7 cm;

blade broadly hastate to hastate-cordate or triangular, (2–)6.5–13(–18) × (1–)6–11(–16) cm, base truncate to truncate-cordate, margins broadly hastate with lobes divergent, ciliate, sometimes also retrorsely prickly, apex acuminate, faces appressed-pubescent or, rarely, glabrous adaxially, stellate-pubescent or, rarely, glabrous abaxially, major veins often bearing prickles.

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 paniclelike, uninterrupted, 5–12 × 3–8 mm;

peduncle 10–80 mm, retrorsely prickly proximally, stellate-pubescent and stipitate-glandular distally, glands red or pink;

ocreolae usually overlapping, sometimes not overlapping proximally, margins eciliate or ciliate with bristles to 0.5 mm.

Pedicels

mostly ascending, 1–1.5 mm.

mostly ascending, 2–3 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.

2–4 per ocreate fascicle;

perianth pink or red, often whitish green proximally, glabrous, accrescent, not becoming blue and fleshy in fruit;

tepals 4, connate 1/3–1/2 their length, broadly elliptic, 5–6 mm, apex acute to obtuse;

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

anthers pink, elliptic;

styles 2, distinct.

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, dark brown to black, biconvex, 3.5–6 × 3–4 mm, shiny, smooth.

2n

= 40.

Persicaria sagittata

Persicaria arifolia

Phenology Flowering Jun–Oct. Flowering Jul–Oct.
Habitat Moist shaded sites, meadows, pastures, fens, swamps, shorelines of ponds and streams Shaded swamps, ponds, tidal marshes along rivers, wet ravines in forests
Elevation 0-1000 m (0-3300 ft) 0-600 m (0-2000 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; GA; IL; IN; KY; LA; MA; MD; ME; MI; MN; MO; NC; NH; NJ; NY; OH; PA; RI; SC; TN; VA; VT; WA; WI; WV; NB; NS; ON; PE; QC
[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.)

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. 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. wallichii
Synonyms Polygonum sagittatum, Polygonum sagittatum var. gracilentum, Tracaulon sagittatum, Truellum sagittatum Polygonum arifolium, Polygonum arifolium var. lentiforme, Polygonum arifolium var. pubescens, Polygonum sagittatum var. pubescens, Tracaulon arifolium, Truellum arifolium
Name authority (Linnaeus) H. Gross: Beih. Bot. Centralbl. 37(2): 113. (1919) (Linnaeus) Haraldson: Acta Univ. Upsal., Symb. Bot. Upsal. 22: 72. (1978)
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