Persicaria sagittata |
Persicaria chinensis |
|
---|---|---|
arrow-leaf knotweed, arrow-leaf tearthumb, arrow-vine, renouée sagittée |
Chinese knotweed, Chinese smartweed |
|
Habit | Plants annual, 3–20 dm; roots also often arising from proximal nodes. | Plants perennial, 7–10 dm; roots not also arising from proximal nodes; rhizomes present. |
Stems | scandent, ribbed, glabrous; prickles 1–1.5 mm. |
ascending to erect, sometimes scandent, glabrous or retrorsely hispid. |
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 brownish, cylindric, 15–25(–50) mm, coriaceous proximally, chartaceous distally, base often inflated, margins oblique, eciliate, surface glabrous or pubescent; petiole 1–2.5 cm, winged at least distally; blade lanceolate to ovate or elliptic, 4–16 × 1.5–8 cm, base truncate to broadly cordate, margins glabrous or antrorsely scabrous with whitish hairs, apex acuminate, faces glabrous or hispid abaxially and adaxially, sometimes pubescent only along veins abaxially, not glandular-punctate but often minutely reddish-punctate 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. |
terminal or terminal and axillary, 3–6 × 3–6 mm; peduncle 10–30 mm, stipitate-glandular along entire length; ocreolae overlapping, margins eciliate. |
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. |
1–3 per ocreate fascicle; perianth white to pink, campanulate, glabrous, accrescent; tepals 5, ovate, 3–4 mm, apex acute to obtuse; stamens 8, filaments distinct, free; anthers red or purple, elliptic; 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 in fleshy, bluish black perianth, black, 3-gonous, 2.8–4 × 2–3 mm, dull, minutely punctuate. |
2n | = 40. |
|
Persicaria sagittata |
Persicaria chinensis |
|
Phenology | Flowering Jun–Oct. | Flowering Jul–Oct. |
Habitat | Moist shaded sites, meadows, pastures, fens, swamps, shorelines of ponds and streams | Disturbed places |
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
|
MA; MD; NJ; Asia [Introduced in North America; introduced also in the Pacific Islands (Hawaii)] |
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.) |
Varieties of Persicaria chinensis have been distinguished on the basis of stem pubescence, leaf shape, and leaf size. Whether those taxa merit recognition in the flora area is uncertain. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 5, p. 577. | FNA vol. 5, p. 580. |
Parent taxa | Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Echinocaulon | Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Cephalophilon |
Sibling taxa | ||
Synonyms | Polygonum sagittatum, Polygonum sagittatum var. gracilentum, Tracaulon sagittatum, Truellum sagittatum | Polygonum chinense |
Name authority | (Linnaeus) H. Gross: Beih. Bot. Centralbl. 37(2): 113. (1919) | (Linnaeus) H. Gross: Bot. Jahrb. Syst. 49: 269. (1913) |
Web links |
|