Polygonum majus |
Polygonum polygaloides |
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large Douglas' knotweed, large knotweed, Palouse knotweed, wiry knotweed |
close-flower knotweed, close-flower knotweed (ssp. confertiflorum), Kellogg's knotweed (ssp. kelloggii), milkwort knotweed, polygala knotweed, whitemargin knotweed |
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Habit | Herbs. | Herbs. | ||||||||||||||||
Stems | erect, green, simple or branched, ± wiry, 15–60 cm, usually papillose-scabridulous. |
erect, green, usually divaricately branched, rarely simple, ± wiry, (2–)6–20(–25) cm, glabrous. |
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Leaves | uniformly distributed, articulated to ocreae, basal leaves often caducous, distal leaves abruptly reduced to bracts, articulated to ocreae; ocrea 5–12 mm, glabrous or papillose-scabridulous, proximal part cylindric, distal part lacerate or disintegrating into fibers; petiole 0.1–2 mm; blade 1-veined, not pleated, linear to narrowly oblong or lanceolate, 15–70 × 2–8 mm, margins revolute, papillose-denticulate, apex acute or mucronate. |
uniformly distributed, articulated to ocreae, basal leaves often caducous, distal leaves abruptly reduced to bracts; ocrea 4–8 mm, glabrous, proximal part cylindric, distal part silvery, with inconspicuous veins, lacerate; petiole absent; blade 3-veined, lateral veins sometimes inconspicuous, without pleats, narrowly linear, 10–40 × 1–2.5 mm, margins ± revolute, smooth, apex acute or mucronate. |
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Inflorescences | axillary and terminal, spikelike, elongate; cymes spaced along branches, 2–5-flowered. |
axillary and terminal, spikelike, subglobose to cylindric; cymes in most axils or crowded distally, 1–3-flowered. |
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Pedicels | exserted from ocreae, reflexed, 0.5–1 mm. |
enclosed in ocreae, erect, 0.1–2 mm, sometimes absent. |
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Flowers | open or semi-open; perianth (3.5–)4–5 mm; tube 9–17% of perianth length; tepals overlapping, uniformly white to pink, petaloid, oblong to oblong-obovate, cucullate, navicular in distal 1/4, apex rounded; midveins unbranched or with short lateral branches; stamens 8. |
mostly closed; perianth 1.5–3 mm; tube 19–40% of perianth length; tepals overlapping, uniformly white, pink, or red, petaloid, oblong-lanceolate, ± navicular, apex acute to acuminate; midveins usually unbranched or with 2 lateral branches proximally, moderately to strongly thickened, tepals appearing ± keeled; stamens 3–8. |
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Achenes | enclosed in perianth, black, elliptic, 3.5–5 mm, faces subequal, shiny or dull, smooth or striate-tubercled. |
enclosed in perianth, light yellow, light brown, or greenish brown to dark brown, ovate to lanceolate, 1.3–2.5 mm, faces subequal, shiny or dull, smooth or reticulate with longitudinal ridges. |
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Polygonum majus |
Polygonum polygaloides |
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Phenology | Flowering May–Aug. | |||||||||||||||||
Habitat | Dry plains, meadows, sometimes on serpentine | |||||||||||||||||
Elevation | 500-2000 m (1600-6600 ft) | |||||||||||||||||
Distribution |
CA; CO; ID; NV; OR; UT; WA; WY; BC
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AZ; CA; CO; ID; MT; NM; NV; OR; UT; WA; WY; AB; BC; SK
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Discussion | Subspecies 4 (4 in the flora). J. C. Hickman’s (1993c) treatment of the Polygonum polygaloides complex is provisionally accepted here. Most of the intermediate specimens occur between subspp. confertiflorum, esotericum, and kelloggii. Alternatively, P. polygaloides could be recognized in the narrow sense and the three other taxa could be treated as subspecies of a separate P. kelloggii, the earliest available binomial. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 5, p. 570. | FNA vol. 5, p. 565. | ||||||||||||||||
Parent taxa | Polygonaceae > subfam. Polygonoideae > Polygonum > sect. Duravia | Polygonaceae > subfam. Polygonoideae > Polygonum > sect. Duravia | ||||||||||||||||
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Synonyms | P. coarctatum var. majus, P. douglasii subsp. majus | |||||||||||||||||
Name authority | (Meisner) Piper: Fl. Palouse Reg., 63. (1901) | Meisner: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 14: 101. (1856) | ||||||||||||||||
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