The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

broad-leaf knotweed, broad-leaf or leafy dwarf knotweed, leafy dwarf knotweed, little mountain knotweed, zigzag knotweed

Habit Herbs.
Stems

prostrate to erect, often zigzagged, reddish brown, simple or branched from base, wiry, 2–30 cm, papillose-scabrid-ulous.

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.

Inflorescences

axillary;

cymes from near stem and branch bases, sometimes also crowded at branch apices, 1–3-flowered.

Pedicels

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.

Achenes

enclosed in perianth or tip exserted, black, elliptic to ovate, 1.8–2.3 mm, faces subequal, smooth, shiny.

Polygonum minimum

Polygonum humifusum

Phenology Flowering Jul–Sep.
Habitat Alpine to subalpine sites, open or semibarren soil
Elevation 1500-3300 m (4900-10800 ft)
Distribution
from FNA
AK; CA; CO; ID; MT; NV; OR; UT; WA; WY; AB; BC
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; NT; NU; YT; e Asia
[BONAP county map]
Discussion

Subspecies 2 (1 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 5, p. 569. FNA vol. 5, p. 555.
Parent taxa Polygonaceae > subfam. Polygonoideae > Polygonum > sect. Duravia Polygonaceae > subfam. Polygonoideae > Polygonum
Sibling taxa
P. achoreum, P. argyrocoleon, P. austiniae, P. aviculare, P. bidwelliae, P. bolanderi, P. californicum, P. cascadense, P. douglasii, P. engelmannii, P. erectum, P. fowleri, P. glaucum, P. heterosepalum, P. hickmanii, P. humifusum, P. majus, P. marinense, P. nuttallii, P. oxyspermum, P. paronychia, P. parryi, P. patulum, P. plebeium, P. polygaloides, P. ramosissimum, P. sawatchense, P. shastense, P. spergulariiforme, P. striatulum, P. tenue, P. utahense
P. achoreum, P. argyrocoleon, P. austiniae, P. aviculare, P. bidwelliae, P. bolanderi, P. californicum, P. cascadense, P. douglasii, P. engelmannii, P. erectum, P. fowleri, P. glaucum, P. heterosepalum, P. hickmanii, P. majus, P. marinense, P. minimum, P. nuttallii, P. oxyspermum, P. paronychia, P. parryi, P. patulum, P. plebeium, P. polygaloides, P. ramosissimum, P. sawatchense, P. shastense, P. spergulariiforme, P. striatulum, P. tenue, P. utahense
Subordinate taxa
P. humifusum subsp. caurianum
Synonyms P. torreyi
Name authority S. Watson: Botany (Fortieth Parallel), 315. (1871) C. Merck ex K. Koch: Linnaea 22: 205. (1849)
Web links