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

bog smartweed, bristly smartweed

Habit Plants annual, 2–15 dm; roots also often arising from proximal nodes. Plants perennial, 5–15 dm; roots also often arising from proximal nodes; rhizomes present, stolons sometimes produced on plants in water.
Stems

scandent, ribbed, glabrous;

prickles 0.5–1 mm.

ascending or erect, branched distally, slightly ribbed, glabrous or loosely appressed- to spreading-hirsute near nodes.

Leaves

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.

ocrea brown, cylindric, 10–20 mm, chartaceous, base usually inflated, margins truncate, ciliate with bristles 6–12 mm, surface strigose and with loosely ascending to spreading hairs at least proximally, not glandular-punctate;

petiole 0.1–0.5 cm, spreading-hirsute, leaves sometimes sessile;

blade without dark triangular or lunate blotch adaxially, lanceolate, (3–)6–15(–18) × (1.5–)2–3.2(–4.8) cm, base tapered to truncate, margins appressed-ciliate, apex acute to acuminate, faces sparsely hirsute to loosely appressed hirsute abaxially and adaxially.

Inflorescences

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.

mostly terminal, erect, uninterrupted, 20–80 × 4–8 mm;

peduncle 10–70 mm, strigose;

ocreolae overlapping, margins ciliate with bristles (0.6–)1–3(–5) mm.

Pedicels

mostly ascending, 2–3 mm.

ascending, 1–3 mm.

Flowers

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.

(1–)2–4(–5) per ocreate fascicle, homostylous;

perianth greenish proximally, creamy or tan distally, occasionally tinged pink, glabrous, not glandular-punctate, nonaccrescent;

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

stamens 5, included;

anthers pink or red, elliptic;

styles 3, connate proximally.

Achenes

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

included or apex exserted, brown to black, 3-gonous, (1.5–)2–2.5 × 1.2–1.7 mm, shiny, smooth.

2n

= 20.

Persicaria arifolia

Persicaria setacea

Phenology Flowering Jul–Oct. Flowering Jul–Oct.
Habitat Shaded swamps, ponds, tidal marshes along rivers, wet ravines in forests Alluvial woods, swamp forests
Elevation 0-600 m (0-2000 ft) 0-300 m (0-1000 ft)
Distribution
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]
from FNA
AL; AR; DE; FL; GA; IL; IN; KY; LA; MA; MD; MI; MO; MS; NC; NJ; NY; OH; OK; PA; RI; SC; TN; TX; VA; WA
[WildflowerSearch map]
[BONAP county map]
Discussion

C. B. McDonald (1980) showed that Persicaria setacea is closely related to P. hirsuta and P. hydropiperoides. Hybrids between P. setacea and P. hirsuta have been produced experimentally but appear to be rare in the wild. Persicaria setacea and P. hydropiperoides occasionally occur in mixed populations but do not hybridize (McDonald). Persicaria setacea sometimes intergrades morphologically with P. hydropiperoides, especially in New England. Specimens of P. setacea without the characteristic ascending or spreading hairs on the ocreae usually can be distinguished from P. hydropiperoides by the extent of adnation of the hairs to the ocreae—up to one-third their lengths in P. setacea, but one-third to two-thirds their lengths in P. hydropiperoides.

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

Source FNA vol. 5, p. 577. FNA vol. 5, p. 588.
Parent taxa Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Echinocaulon Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Persicaria
Sibling taxa
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
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. virginiana, P. wallichii
Synonyms Polygonum arifolium, Polygonum arifolium var. lentiforme, Polygonum arifolium var. pubescens, Polygonum sagittatum var. pubescens, Tracaulon arifolium, Truellum arifolium Polygonum setaceum, Polygonum hydropiperoides var. setaceum, Polygonum setaceum var. interjectum, Polygonum setaceum var. tonsum
Name authority (Linnaeus) Haraldson: Acta Univ. Upsal., Symb. Bot. Upsal. 22: 72. (1978) (Baldwin) Small: Fl. S.E. U.S., 379. (1903)
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