Persicaria capitata |
Persicaria pensylvanica |
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Himalayan smartweed, Japanese knotweed, pink bubble persicaria, pink-head knotweed, pink-head persicaria, pinkhead smartweed |
Pennsylvania smartweed, pinkweed, renouée de pennsylvanie |
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Habit | Plants annual or perennial, 0.5–5 dm; roots also often arising from proximal nodes. | Plants annual, 1–20 dm; roots also occasionally arising from basal nodes; rhizomes and stolons absent. |
Stems | prostrate, glabrous or glandular-pubescent. |
ascending to erect, simple or branched, ribbed, glabrous or appressed-pubescent distally, eglandular or stipitate-glandular distally. |
Leaves | ocrea brown or reddish brown, cylindric to funnelform, 5–12 mm, chartaceous, base inflated or not, margins oblique, eciliate or ciliate with bristles to 1.5 mm, surface lanate, sometimes also glandular-pubescent; petiole 2–5 mm, winged distally; blade ovate to elliptic, 1.5–4(–6) × 0.6–2.5(–3.3) cm, base cuneate or tapering, margins ciliate with reddish, multicellular hairs, apex acute, faces glandular-pubescent abaxially and adaxially, not glandular-punctate. |
ocrea brownish, cylindric, 5–20 mm, chartaceous, base inflated, margins truncate, eciliate or ciliate with bristles to 0.5 mm, surface glabrous or appressed-pubescent, eglandular; petiole 0.1–2(–3) cm, glabrous or appressed-pubescent; blade sometimes with dark triangular or lunate blotch adaxially, narrowly to broadly lanceolate, 4–17(–23) × (0.5–)1–4.8 cm, base tapered to cuneate, margins antrorsely scabrous, apex acuminate, faces glabrous or appressed-pubescent, eglandular or glandular-punctate abaxially and occasionally adaxially. |
Inflorescences | terminal, 5–20 × 7-18 mm; peduncle 10–40 mm, glabrous or stipitate-glandular in distal 1/5; ocreolae overlapping, margins eciliate. |
terminal and axillary, erect or rarely nodding, uninterrupted, 5–50 × 5–15 mm; peduncle 10–55(–70) mm, glabrous or pubescent, usually stipitate-glandular; ocreolae overlapping, margins eciliate or ciliate with bristles to 0.5 mm. |
Pedicels | spreading, 0.5–1 mm. |
ascending, 1.5–4.5 mm. |
Flowers | 1–5 per ocreate fascicle; perianth greenish white proximally, pinkish distally, urceolate, glabrous, nonaccrescent; tepals 5, elliptic, 2–3 mm, apex acute to obtuse; stamens 8, filaments distinct, free; anthers pink to red, elliptic; styles 3, connate to middle or distally. |
2–14 per ocreate fascicle, homostylous; perianth greenish white to roseate, glabrous, not glandular-punctate, accrescent; tepals 5, connate ca. 1/4–1/3 their length, obovate to elliptic, 2.5–5 mm, veins prominent, not anchor-shaped, margins entire, apex obtuse to rounded; stamens 6–8, included; anthers yellow, pink, or red, elliptic; styles 2(–3), connate at bases. |
Achenes | included, reddish brown to brownish black, 3-gonous, 1.5–2.2 × 1–1.5 mm, shiny, smooth or minutely punctate. |
included or apex exserted, brown to black, discoid or, rarely, 3-gonous, without central hump on 1 side, 2.1–3.4 × 1.8–3 mm, shiny, smooth. |
2n | = 88. |
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Persicaria capitata |
Persicaria pensylvanica |
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Phenology | Flowering Jun–Sep. | Flowering May–Dec. |
Habitat | Disturbed, urban places | Moist, disturbed places, ditches, riverbanks, cultivated fields, shorelines of ponds and reservoirs |
Elevation | 0-500 m (0-1600 ft) | 0-1800 m (0-5900 ft) |
Distribution |
CA; LA; OR; Asia (Bhutan, w China, n India, Nepal) [Introduced in North America; introduced also in the Pacific Islands (Hawaii)]
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AK; AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; PA; RI; SC; SD; TN; TX; UT; VA; VT; WI; WV; WY; NB; NF; NS; ON; QC; South America (Ecuador); Europe (England, Spain)
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Discussion | Persicaria capitata is planted as a garden groundcover. It escapes infrequently in the flora area; once established outside of cultivation it can be difficult to eradicate. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Persicaria pensylvanica is a morphologically variable allotetraploid, with P. lapathifolia probably one of the parents (L. L. Consaul et al. 1991). Three or four varieties (under Polygonum) often have been accepted in North American floras; the characters on which these are based vary greatly within and among populations. J. W. Taylor-Lehman (1987) concluded that Polygonum pensylvanicum is best treated as a polymorphic species without infraspecific taxa, based on specimens primarily from Ohio. The heterostylous Persicaria bicornis often is included in P. pensylvanica. A single chromosome count of 2n = 22 reported by Á. Löve and D. Löve (1982), which could not be confirmed by Consaul et al. because the voucher could not be found, is excluded. Flowers with three styles and trigonous achenes are produced; they are exceedingly rare and probably mostly overlooked. Several Native American tribes prepared infusions and decoctions from P. pensylvanica, which they used as drugs for humans and horses (D. E. Moerman 1998). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 5, p. 579. | FNA vol. 5, p. 588. |
Parent taxa | Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Cephalophilon | Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Persicaria |
Sibling taxa | ||
Synonyms | Polygonum capitatum | Polygonum pensylvanicum, P. mississippiensis, P. pensylvanica var. dura, Polygonum omissum, Polygonum pensylvanicum var. durum, Polygonum pensylvanicum var. eglandulosum, Polygonum pensylvanicum var. laevigatum, Polygonum pensylvanicum var. nesophilum, Polygonum pensylvanicum var. rosiflorum |
Name authority | (Buchanan-Hamilton ex D. Don) H. Gross: Bot. Jahrb. Syst. 49: 277. (1913) | (Linnaeus) M. Gómez: Anales Inst. Segunda Enseñ. 2: 278. (1896) |
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