Polygonum parryi |
Polygonum majus |
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Parry's knotweed, Parry's or prickly knotweed, prickly knotweed |
large Douglas' knotweed, large knotweed, Palouse knotweed, wiry knotweed |
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Habit | Herbs, compact, often cushion-like. | Herbs. |
Stems | erect, green-brown, simple or branched from base, not wiry, 2–5(–8) cm, glabrous. |
erect, green, simple or branched, ± wiry, 15–60 cm, usually papillose-scabridulous. |
Leaves | ± uniformly distributed, dense, not articulated to ocreae, basal leaves ± persistent, distal leaves gradually reduced to bracts; ocrea 2–4(–5) mm, glabrous, proximal part cylindric, distal part deeply lacerate, disintegrating into white, curled fibers; petiole absent; blade 3-veined, without pleats, linear-lanceolate, subulate, 5–13(–20) × 0.4–1 mm, margins revolute, smooth, apex spine-tipped. |
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. |
Inflorescences | axillary; cymes in most axils, 1-flowered. |
axillary and terminal, spikelike, elongate; cymes spaced along branches, 2–5-flowered. |
Pedicels | absent. |
exserted from ocreae, reflexed, 0.5–1 mm. |
Flowers | closed; perianth 1.5–2(–2.5) mm; tube 6–15% of perianth length; tepals overlapping, usually reddish with white margins, petaloid, oblong, navicular, apex acute; midveins unbranched; stamens 8. |
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. |
Achenes | slightly exserted from perianth at maturity, dark brown, ovate, 1.2–1.6(–2) mm, faces subequal, shiny, smooth. |
enclosed in perianth, black, elliptic, 3.5–5 mm, faces subequal, shiny or dull, smooth or striate-tubercled. |
Polygonum parryi |
Polygonum majus |
|
Phenology | Flowering May–July. | Flowering May–Aug. |
Habitat | Vernally moist, open, sandy or rocky places | Dry plains, meadows, sometimes on serpentine |
Elevation | 500-2000 m (1600-6600 ft) | 500-2000 m (1600-6600 ft) |
Distribution |
CA; WA
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CA; CO; ID; NV; OR; UT; WA; WY; BC
|
Source | FNA vol. 5, p. 563. | FNA vol. 5, p. 570. |
Parent taxa | Polygonaceae > subfam. Polygonoideae > Polygonum > sect. Duravia | Polygonaceae > subfam. Polygonoideae > Polygonum > sect. Duravia |
Sibling taxa | ||
Synonyms | P. coarctatum var. majus, P. douglasii subsp. majus | |
Name authority | Greene: Bull. Torrey Bot. Club 8: 99. (1881) | (Meisner) Piper: Fl. Palouse Reg., 63. (1901) |
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