Polygonum minimum |
Polygonum cascadense |
|
---|---|---|
broad-leaf knotweed, broad-leaf or leafy dwarf knotweed, leafy dwarf knotweed, little mountain knotweed, zigzag knotweed |
Cascade knotweed |
|
Habit | Herbs. | Herbs. |
Stems | prostrate to erect, often zigzagged, reddish brown, simple or branched from base, wiry, 2–30 cm, papillose-scabrid-ulous. |
spreading to erect, zigzagged, green, simple or branched from base, wiry, 5–12(–15) 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 persistent, distal leaves abruptly reduced to bracts; ocrea 2–5 mm, glabrous, proximal part funnelform, distal part lacerate; petiole essentially absent; blade 1-veined, not pleated, oblanceolate to obovate, 5–20 × 2–5 mm, margins revolute, never touching along midrib, sparsely papillose-denticulate, apex rounded or apiculate. |
Inflorescences | axillary; cymes from near stem and branch bases, sometimes also crowded at branch apices, 1–3-flowered. |
axillary and terminal, spikelike, dense; cymes congested at tips of stems and branches, 3–5-flowered. |
Pedicels | enclosed in ocreae, erect to spreading, 2–3 mm. |
enclosed in ocreae, erect to spreading, 2–3 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; perianth 2–2.5 mm; tube 12–25% of perianth length; tepals overlapping, uniformly white, petaloid, oblong to obovate, cucullate, navicular in distal 1/4, apex rounded; midveins unbranched; 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 exserted from perianth, black, ovate to ovate-oblong, 1.8–2.1 mm, faces subequal, shiny, smooth. |
Polygonum minimum |
Polygonum cascadense |
|
Phenology | Flowering Jul–Sep. | Flowering Jun–Sep. |
Habitat | Alpine to subalpine sites, open or semibarren soil | Dry, usually rocky slopes, often on serpentine |
Elevation | 1500-3300 m (4900-10800 ft) | 1600-1800 m (5200-5900 ft) |
Distribution |
AK; CA; CO; ID; MT; NV; OR; UT; WA; WY; AB; BC
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OR
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Source | FNA vol. 5, p. 569. | FNA vol. 5, p. 571. |
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. Baker: Madroño 10: 62, plate 1, fig. 1. (1949) |
Web links |
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