Polygonum ramosissimum |
Polygonum tenue |
|||||
---|---|---|---|---|---|---|
bushy knotweed, yellow knotweed, yellow-flower knotweed |
pleat-leaf knotweed, slender knotweed |
|||||
Habit | Plants yellowish green or bluish green, (dark brown to black after drying in subsp. prolificum), heterophyllous or homophyllous. | Herbs. | ||||
Stems | erect, usually profusely branched in distal 1/2, not wiry, 10–100(–200) cm. |
erect, green or brown-ish, simple or branched from below middle, not wiry, 5–50 cm, glabrous or papillose-scabridulous. |
||||
Leaves | ocrea 6–12(–15) mm, proximal part cylindric, distal part silvery, soon disintegrating into persistent brown fibers; petiole 2–4 mm; blade variable, light yellowish green to bluish green, proximal often caducous, narrowly elliptic, lanceolate, or oblanceolate, rarely ovate, 8–70 × 4–18(–35) mm, margins flat, apex acute to acuminate or obtuse; distal leaves, either overtopping or shorter than or equaling flowers. |
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 or axillary and terminal, spikelike; cymes uniformly distributed or crowded toward tips of branches, 2–5-flowered. |
axillary and terminal, spikelike, slender, elongate; cymes spaced along branches, 1–2(–3)-flowered. |
||||
Pedicels | enclosed in or exserted from ocreae, 1–6 mm. |
enclosed in ocreae, erect, 1–1.5 mm. |
||||
Flowers | closed; perianth (2–)2.2–3.6(–4) mm; tube 20–38% of perianth length; tepals overlapping, greenish yellow with greenish yellow or yellow, rarely pink or white, margins, petaloid or sepaloid, not keeled, elliptic to oblong, cucullate; midveins thickened or not; stamens 3–6(–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 exserted from perianth, dark brown, ovate, 3-gonous, 1.6–3.5 mm, faces subequal, concave, apex not beaked, edges straight, shiny or dull, usually smooth to roughened, sometimes uniformly or obscurely tubercled; late-season achenes common, 4–15 mm. |
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 ramosissimum |
Polygonum tenue |
|||||
Phenology | Flowering Jun–Oct. | |||||
Habitat | Dry acid soils in exposed sites | |||||
Elevation | 100-1000 m (300-3300 ft) | |||||
Distribution |
AR; AZ; CA; CO; CT; DE; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NS; NT; ON; PE; QC; SK
|
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
|
||||
Discussion | Subspecies 2 (2 in the flora). Polygonum ramosissimum exhibits considerable morphological complexity and is similar in difficulty to the P. aviculare complex. Further research is necessary to understand the infraspecific variability of this species (M. Costea and F. J. Tardif 2003b). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|||||
Key |
|
|||||
Source | FNA vol. 5, p. 551. | FNA vol. 5, p. 567. | ||||
Parent taxa | Polygonaceae > subfam. Polygonoideae > Polygonum > sect. Polygonum | Polygonaceae > subfam. Polygonoideae > Polygonum > sect. Duravia | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | P. tenue var. protrusum | |||||
Name authority | Michaux: Fl. Bor.-Amer. 1: 237. (1803) | Michaux: Fl. Bor.-Amer. 1: 238. (1803) | ||||
Web links |
|