Polygonum minimum |
Polygonum hickmanii |
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broad-leaf knotweed, broad-leaf or leafy dwarf knotweed, leafy dwarf knotweed, little mountain knotweed, zigzag knotweed |
Hickman's knotweed, Scotts Valley polygonum |
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Habit | Herbs. | Herbs, compact, often cushion-like. |
Stems | prostrate to erect, often zigzagged, reddish brown, simple or branched from base, wiry, 2–30 cm, papillose-scabrid-ulous. |
erect, color unknown, simple to profusely branched from near base, not wiry, 2–5 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. |
persistence and crowded at brance tips, not articulated to ocreae; ocrea 4–6 mm, glabrous, proximal part cylindric, distal part silvery, disintegrating nearly to base into straight fibers; petiole absent; blade 3-veined, without pleats, linear, 5–35 × 1–1.5 mm, margins revolute, smooth, apex acuminate. |
Inflorescences | axillary; cymes from near stem and branch bases, sometimes also crowded at branch apices, 1–3-flowered. |
axillary; cymes insertion unknown, 1-flowered. |
Pedicels | enclosed in ocreae, erect to spreading, 2–3 mm. |
absent. |
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. |
closed; perianth 2–3 mm; tube 6–18 % of perianth length, tepals imbrication unknown, white with whitish or pink margins, petaloid, oblong, apex acute, mucronate; midveins unbranched; stamens 8; anthers orange-pink. |
Achenes | enclosed in perianth or tip exserted, black, elliptic to ovate, 1.8–2.3 mm, faces subequal, smooth, shiny. |
enclosed in perianth, olive brown, ovate, 2–2.3 mm, faces subequal, shiny, smooth. |
Polygonum minimum |
Polygonum hickmanii |
|
Phenology | Flowering Jul–Sep. | Flowering May–Oct. |
Habitat | Alpine to subalpine sites, open or semibarren soil | Open, seasonally dry grasslands |
Elevation | 1500-3300 m (4900-10800 ft) | 200-300 m (700-1000 ft) |
Distribution |
AK; CA; CO; ID; MT; NV; OR; UT; WA; WY; AB; BC
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CA |
Discussion | Of conservation concern. The above description is based on the original one by Hinds and Morgan. Polygonum hickmanii is known only from the northern end of Scotts Valley in Santa Cruz County. (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) | H. R. Hinds & Rand. Morgan: Novon 5: 336. (1995) |
Web links |
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