Polygonum minimum |
Polygonum shastense |
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broad-leaf knotweed, broad-leaf or leafy dwarf knotweed, leafy dwarf knotweed, little mountain knotweed, zigzag knotweed |
Shasta knotweed |
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Habit | Herbs. | Subshrubs. |
Stems | prostrate to erect, often zigzagged, reddish brown, simple or branched from base, wiry, 2–30 cm, papillose-scabrid-ulous. |
prostrate to ascending, brown, branched, gnarled, not wiry, 5–40 cm, glabrous. |
Leaves | evenly distributed or crowded at branch tips, articulated to ocreae, basal leaves persistent, hardly reduced distally; ocrea 1–4 mm, papillose-scabridulous, proximal part cylindric, distal part entire or dentate-lacerate; petiole 0.1–3 mm; blade 1-veined, not pleated, narrowly elliptic, elliptic, ovate, obovate, or subround, 6–27 × 3–8 mm, margins flat, smooth, irregularly thickened or papillose-denticulate, apex apiculate, green adaxially. |
± uniformly distributed, articulated to ocreae, basal leaves caducous or persistent, distal leaves not reduced in size; ocrea 3–5 mm, glabrous, proximal part cylindric, distal part membranous, deciduous with leaves; petiole 0–0.5 mm; blade 1-veined, without pleats, lanceolate to elliptic, 5–25 × 2–5 mm, coriaceous, margins revolute, smooth, apex acute. |
Inflorescences | axillary; cymes from near stem and branch bases, sometimes also crowded at branch apices, 1–3-flowered. |
axillary; cymes in distal axils, 2–6-flowered. |
Pedicels | enclosed in ocreae, erect to spreading, 2–3 mm. |
enclosed in or slightly exserted from ocreae, erect, 2–4 mm. |
Flowers | semi-open or closed; perianth 1.8–2.5 mm; tube 22–29% of perianth length; tepals overlapping, greenish with narrow white or pink margins, almost sepaloid, oblong, cucullate, ± navicular, apex rounded; midveins thickened, unbranched; stamens 8. |
open or semi-open; perianth 5–9 mm; tube 7–15% of perianth length, tepals partially overlapping, uniformly pink or white, petaloid, ovate to ovate-round, apex rounded; midveins with numerous branched lateral veins; stamens 8. |
Achenes | enclosed in perianth or tip exserted, black, elliptic to ovate, 1.8–2.3 mm, faces subequal, smooth, shiny. |
enclosed in or slightly exserted from perianth, brown, narrowly ovate, 3–4 mm, faces subequal, shiny, smooth. |
Polygonum minimum |
Polygonum shastense |
|
Phenology | Flowering Jul–Sep. | Flowering Jul–Sep. |
Habitat | Alpine to subalpine sites, open or semibarren soil | Rocky or gravelly slopes |
Elevation | 1500-3300 m (4900-10800 ft) | 2100-3400 m (6900-11200 ft) |
Distribution |
AK; CA; CO; ID; MT; NV; OR; UT; WA; WY; AB; BC
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CA; NV; OR
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Discussion | Polygonum shastense may be cultivated in rock gardens in rock crevices with favorable water regime and shaded in summer. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 5, p. 569. | FNA vol. 5, p. 563. |
Parent taxa | Polygonaceae > subfam. Polygonoideae > Polygonum > sect. Duravia | Polygonaceae > subfam. Polygonoideae > Polygonum > sect. Duravia |
Sibling taxa | ||
Synonyms | P. torreyi | |
Name authority | S. Watson: Botany (Fortieth Parallel), 315. (1871) | W. H. Brewer: Proc. Amer. Acad. Arts 8: 400. (1872) |
Web links |
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