Persicaria sagittata |
Persicaria hirsuta |
|
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arrow-leaf knotweed, arrow-leaf tearthumb, arrow-vine, renouée sagittée |
hairy smartweed |
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Habit | Plants annual, 3–20 dm; roots also often arising from proximal nodes. | Plants perennial, 3–9 dm; roots also often arising from proximal nodes; rhizomes present. |
Stems | scandent, ribbed, glabrous; prickles 1–1.5 mm. |
decumbent to ascending or erect, branched, without noticeable ribs, brownish-hirsute on internodes. |
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 brown to reddish brown, cylindric, 6–12 mm, chartaceous, base sometimes inflated, margins truncate, eciliate or ciliate with bristles 4–7.5 mm, surface hirsute, not glandular-punctate; petiole 0.1(–0.3) cm, hirsute, leaves sometimes sessile; blade without dark triangular or lunate blotch adaxially, ovate to lanceolate, (2–)4–8 × (0.5–)1–2.5 cm, base rounded to cordate, margins strigose to hirsute, apex acute to acuminate, faces sparingly hirsute abaxially and adaxially, midvein usually hirsute 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. |
mostly terminal, erect, interrupted proximally, usually uninterrupted distally, 20–80 × 4–8 mm; peduncle 30–60 mm, hirsute or, sometimes, nearly glabrous distally; ocreolae overlapping distally, usually not overlapping proximally, margins ciliate with bristles 0.4–1.5(–2) mm. |
Pedicels | mostly ascending, 1–1.5 mm. |
ascending, 1–2 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, homostylous; perianth white to pink, glabrous, not glandular-punctate, nonaccrescent; tepals 5, connate in proximally 1/3, obovate, 1.5–2 mm, veins not prominent, not anchor-shaped, margins entire, apex obtuse to rounded; stamens 5, included; anthers red, elliptic to 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 or apex exserted, dark brown to brownish black, 3-gonous, 2–2.5 × 1.3–1.8 mm, shiny, smooth. |
2n | = 40. |
= 20. |
Persicaria sagittata |
Persicaria hirsuta |
|
Phenology | Flowering Jun–Oct. | Flowering Jun–Oct. |
Habitat | Moist shaded sites, meadows, pastures, fens, swamps, shorelines of ponds and streams | Sandy soils, open areas in savannahs, pond margins, ditches, often in shallow water |
Elevation | 0-1000 m (0-3300 ft) | 0-100 m (0-300 ft) |
Distribution |
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
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AL; FL; GA; MS; NC; SC |
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.) |
C. B. McDonald (1980) showed that Persicaria hirsuta is closely related to P. setacea and P. hydropiperoides. Hybrids between P. hirsuta and P. setacea have been produced experimentally but appear to be rare in the wild. Although geographically sympatric, the two species generally occupy different habitats. Experimental crosses between P. hirsuta and P. hydropiperoides were unsuccessful (McDonald). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 5, p. 577. | FNA vol. 5, p. 587. |
Parent taxa | Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Echinocaulon | Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Persicaria |
Sibling taxa | ||
Synonyms | Polygonum sagittatum, Polygonum sagittatum var. gracilentum, Tracaulon sagittatum, Truellum sagittatum | Polygonum hirsutum |
Name authority | (Linnaeus) H. Gross: Beih. Bot. Centralbl. 37(2): 113. (1919) | (Walter) Small: Fl. S.E. U.S., 379. (1903) |
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