Persicaria hydropiper |
Persicaria maculosa |
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common smartweed, marsh-pepper smartweed, marshpepper knotweed, mild water-pepper, renouée poivre-d'eau, smartweed, water-pepper, water-pepper smartweed |
heartweed, lady's-thumb, lady's-thumb smartweed, redshank, renouée persicaire, spotted lady's-thumb |
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Habit | Plants annual, 2–8(–10) dm; roots also often arising from proximal nodes; rhizomes and stolons absent. | Plants annual, (0.5–)1–7(–13) dm; roots also often arising from proximal nodes; rhizomes and stolons absent. |
Stems | decumbent to ascending or erect, branched, without noticeable ribs, glabrous, glandular-punctate. |
procumbent, decumbent, ascending, or erect, simple or branched, without obvious ribs, glabrous or appressed-pubescent. |
Leaves | ocrea brown, cylindric or funnelform, (8–)10–15 mm, chartaceous, base inflated, margins truncate, ciliate with bristles 1–4 mm, surface glabrous or strigose, usually glandular-punctate; petiole 0.1–0.8 cm, glandular-punctate, leaves sometimes sessile; blade without dark triangular or lunate blotch adaxially, lanceolate to narrowly rhombic, (1.5–)4–10(–15) × 0.4–2.5 cm, base tapered or cuneate, margins antrorsely strigose, apex acute to acuminate, faces glabrous or scabrous along midveins, glandular-punctate, sometimes obscurely so adaxially. |
ocrea light brown, cylindric, 4–10(–15) mm, chartaceous, base inflated, margins truncate, ciliate with hairs 1–3.5(–5) mm, surface glabrous or strigose, rarely with spreading hairs, not glandular-punctate; petiole 0.1–0.8 cm, glabrous or strigose, leaves sometimes sessile; blade often with dark triangular or lunate blotch adaxially, lanceolate to narrowly ovate, (1–)5–10(–18) × (0.2–)1–2.5(–4) cm, base tapered or cuneate, margins antrorsely strigose, apex acute to acuminate, faces glabrous or strigose, especially along midveins, sometimes glandular-punctate abaxially. |
Inflorescences | terminal and axillary, erect or nodding, interrupted or uninterrupted distally, 30–180 × 5–9 mm; peduncle (0–)10–50 mm, sometimes absent on axillary inflorescences and flowers thus enclosed in ocreae, glabrous, glandular-punctate; ocreolae not overlapping or overlapping distally, margins eciliate or ciliate with bristles to 1 mm. |
terminal and axillary, erect, usually uninterrupted, 10–45(–60) × 7–12 mm; peduncle 10–50 mm, glabrous or, rarely, pubescent; ocreolae overlapping or sometimes interrupted proximally, margins ciliate with bristles 0.2–1.3(–2) mm. |
Pedicels | ascending, 1–3 mm. |
ascending, 1–2.5 mm. |
Flowers | 1–3(–5) per ocreate fascicle, homostylous; perianth greenish proximally, white or pink distally, glandular-punctate with punctae ± uniformly distributed, scarcely accrescent; tepals 4–5, connate ca. 1/3 their length, petaloid, obovate, 2–3.5 mm, veins prominent or not, not anchor-shaped, margins entire, apex obtuse to rounded; stamens 6–8, included; anthers pink or red, elliptic to ovate; styles 2–3, connate proximally. |
4–14 per ocreate fascicle, homostylous; perianth greenish white proximally and roseate distally or entirely roseate, not glandular-punctate, scarcely accrescent; tepals 4–5, connate ca. 1/3 their length, obovate, 2–3.5 mm, veins prominent, not anchor-shaped, margins entire, apex obtuse to rounded; stamens 4–8, included; anthers yellow or pink, ovate; styles 2–3, connate proximally. |
Achenes | included or apex exserted, brownish black, biconvex or 3-gonous, 1.9–3 × 1.5–2 mm, dull, minutely roughened. |
included or apex exserted, brownish black to black, discoid or biconvex to 3-gonous, (1.9–)2–2.7 × (1.5–) 1.8–2.2 mm, shiny, smooth. |
2n | = 20. |
= 44. |
Persicaria hydropiper |
Persicaria maculosa |
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Phenology | Flowering May–Nov. | Flowering Mar–Nov. |
Habitat | Shorelines of lake and ponds, banks of streams and rivers, fens, forested wetlands, pastures, occasionally waste ground | Weedy, moist semiwaste to cultivated areas |
Elevation | 0-1500 m (0-4900 ft) | 0-2500 m (0-8200 ft) |
Distribution |
AK; AL; AR; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; BC; MB; NB; NF; NS; ON; PE; QC; SPM; Europe; nw Africa; Pacific Islands (Hawaii, New Zealand); Australia [Introduced in North America; introduced also in Asia]
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AK; AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NL; NS; ON; PE; QC; SK; YT; SPM; Africa; Greenland; Eurasia; Pacific Islands (New Zealand) [Introduced in North America]
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Discussion | All parts of Persicaria hydropiper have an acrid, pepperlike taste. The plants have a long history of medicinal use in Europe, and the oily exudate produced in multicellular glands can cause skin irritation, hence the common name smartweed (R. S. Mitchell and J. K. Dean 1978). Some Native American tribes used P. hydropiper as a drug to treat a variety of ailments, and the Cherokee and Iroquois consumed it as food (D. E. Moerman 1998). Herbarium specimens of Persicaria hydropiper often are misidentified as P. punctata. In addition to its minutely roughened and dull achenes, P. hydropiper differs from P. punctata frequently in bearing flowers enclosed in the ocreae, the inflorescences thus appearing somewhat leafy. By contrast, inflorescences of P. punctata generally appear terminal and leafless. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
An allozyme study by L. L. Consaul et al. (1991) provided evidence of the allotetraploid origin of Persicaria maculosa, with P. lapathifolium as one of the parents. Plants with stems spreading-hairy and peduncles stipitate-glandular have been named P. maculosa subsp. hirsuticaulis (Danser) S. Ekman & Knutsson. Material referable to this subspecies has not been seen among North American specimens. Hybrids between P. maculosa and P. minor have been documented in Europe (R. H. Roberts 1977). The Cherokee, Chippewa, and Iroquois prepared simple or compound decoctions of Persicaria maculosa, which they used as dermatological, urinary, gastrointestinal, and veterinary aids, for heart medicine, and as an analgesic (D. E. Moerman 1998). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 5, p. 590. | FNA vol. 5, p. 593. |
Parent taxa | Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Persicaria | Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Persicaria |
Sibling taxa | ||
Synonyms | Polygonum hydropiper, Polygonum hydropiper var. projectum | Polygonum persicaria, P. fusiformis, P. vulgaris, Polygonum fusiforme, Polygonum persicaria var. ruderale, Polygonum puritanorum |
Name authority | (Linnaeus) Spach: Hist. Nat. Vég. 10: 536. (1841) | Gray: Nat. Arr. Brit. Pl. 2: 269. (1822) |
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