Polygonum californicum |
Polygonum tenue |
|
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California knotweed |
pleat-leaf knotweed, slender knotweed |
|
Habit | Herbs. | Herbs. |
Stems | erect, green, simple or divaricately branched, ± wiry, 4–40 cm, papillose-scabridulous. |
erect, green or brown-ish, simple or branched from below middle, not wiry, 5–50 cm, glabrous or papillose-scabridulous. |
Leaves | uniformly distributed, not articulated to ocreae, basal leaves usually caducous, distal leaves abruptly reduced to bracts; ocrea 5–10 mm, glabrous or papillose-scabridulous, proximal part cylindric, distal part white or tawny, disintegrating into ± bristly-fringed fibers; petiole absent; blade 3-veined, without pleats, linear, 5–25(–30) × 0.5–2 mm, margins revolute, papillose-denticulate or smooth, apex mucronate or weakly spine-tipped. |
uniformly distributed, articulated to ocreae, basal leaves caducous or persistent, distal leaves abruptly reduced to bracts; ocrea 6–15 mm, glabrous or papillose-scabridulous, proximal part cylindric, distal part soon disintegrating into a few brown fibers; petiole 0.1–1 mm; blade 1-veined, with 1 pleat on each side of midrib, narrowly lanceolate to linear, 25–40 × 1–8 mm, margins usually flat, papillose-denticulate, apex mucronate or cuspidate. |
Inflorescences | axillary; cymes in distal axils, 1-flowered. |
axillary and terminal, spikelike, slender, elongate; cymes spaced along branches, 1–2(–3)-flowered. |
Pedicels | absent. |
enclosed in ocreae, erect, 1–1.5 mm. |
Flowers | open or closed; perianth 2.5–3.5 mm; tube 10–20% of perianth length; tepals overlapping, uniformly white to pink, petaloid, elliptic, navicular, apex acute to acuminate; midveins unbranched; stamens 8. |
closed; perianth 2.5–4.2 mm; tube 15–22% of perianth length; tepals overlapping, green, often brownish when dried, with pink or white margins, petaloid or sepaloid, elliptic, cucullate, navicular, apex rounded; midveins usually unbranched, rarely branched; stamens 8. |
Achenes | enclosed in or slightly exserted from perianth, brown, narrowly elliptic, 1.8–2.2 mm, faces subequal, shiny, smooth. |
enclosed in or slightly exserted from perianth, black, elliptic to oblong, 2.3–4 mm, faces subequal, shiny, smooth or minutely striate-tubercled near edges and apex. |
2n | = 20. |
|
Polygonum californicum |
Polygonum tenue |
|
Phenology | Flowering May–Sep. | Flowering Jun–Oct. |
Habitat | Open places, including serpentine | Dry acid soils in exposed sites |
Elevation | 40-1200 m (100-3900 ft) | 100-1000 m (300-3300 ft) |
Distribution |
CA; OR
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AL; AR; CT; DC; DE; GA; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; NC; NE; NH; NJ; NY; OH; OK; PA; RI; SD; TN; TX; VA; VT; WI; WV; WY; ON
|
Source | FNA vol. 5, p. 564. | FNA vol. 5, p. 567. |
Parent taxa | Polygonaceae > subfam. Polygonoideae > Polygonum > sect. Duravia | Polygonaceae > subfam. Polygonoideae > Polygonum > sect. Duravia |
Sibling taxa | ||
Synonyms | Duravia californica, P. greenei | P. tenue var. protrusum |
Name authority | Meisner: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 14: 100. (1856) | Michaux: Fl. Bor.-Amer. 1: 238. (1803) |
Web links |
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