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

Parry's knotweed, Parry's or prickly knotweed, prickly knotweed

Austin's knotweed, Mrs. Austin's knotweed, Rebecca Austin's knotweed

Habit Herbs, compact, often cushion-like. Herbs.
Stems

erect, green-brown, simple or branched from base, not wiry, 2–5(–8) cm, glabrous.

ascending to erect, green to purplish, much-branched from base, not wiry, 5–10(–20) cm, papillose-scabridulous.

Leaves

± uniformly distributed, dense, not articulated to ocreae, basal leaves ± persistent, distal leaves gradually reduced to bracts;

ocrea 2–4(–5) mm, glabrous, proximal part cylindric, distal part deeply lacerate, disintegrating into white, curled fibers;

petiole absent;

blade 3-veined, without pleats, linear-lanceolate, subulate, 5–13(–20) × 0.4–1 mm, margins revolute, smooth, apex spine-tipped.

uniformly distributed, articulated to ocreae, basal leaves persistent, distal leaves abruptly reduced to bracts, articulated to ocreae;

ocrea 3–5 mm, papillose-scabridulous or glabrous, proximal part funnelform, distal part lacerate;

petiole 0.1–2 mm;

blade 1-veined, not pleated, ovate to elliptic or obovate, 5–15 × 4–7 mm, margins flat or narrowly revolute, papillose-denticulate, apex acute or mucronate.

Inflorescences

axillary;

cymes in most axils, 1-flowered.

axillary and terminal, spikelike, slender;

cymes spaced along branches, 1–4-flowered.

Pedicels

absent.

exserted from ocreae, reflexed, 1–2.5 mm.

Flowers

closed;

perianth 1.5–2(–2.5) mm;

tube 6–15% of perianth length;

tepals overlapping, usually reddish with white margins, petaloid, oblong, navicular, apex acute;

midveins unbranched;

stamens 8.

closed;

perianth (1.8–)2–2.6 mm;

tube 20–28% of perianth length;

tepals overlapping, green or purple, with narrow whitish margins, petaloid or sepaloid, oblong, cucullate, navicular, apex rounded;

midveins unbranched;

stamens 8.

Achenes

slightly exserted from perianth at maturity, dark brown, ovate, 1.2–1.6(–2) mm, faces subequal, shiny, smooth.

enclosed in perianth, black, elliptic to obovate, 2–2.5 mm, faces subequal, shiny, ± smooth.

Polygonum parryi

Polygonum austiniae

Phenology Flowering May–July. Flowering Jun–Sep.
Habitat Vernally moist, open, sandy or rocky places Dry to moist flats on banks, sagebrush plains, and ponderosa pine forests
Elevation 500-2000 m (1600-6600 ft) 1300-1600 m (4300-5200 ft)
Distribution
from FNA
CA; WA
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; ID; MT; NV; OR; WA; WY; AB; BC
[WildflowerSearch map]
[BONAP county map]
Source FNA vol. 5, p. 563. FNA vol. 5, p. 569.
Parent taxa Polygonaceae > subfam. Polygonoideae > Polygonum > sect. Duravia Polygonaceae > subfam. Polygonoideae > Polygonum > sect. Duravia
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. minimum, P. nuttallii, P. oxyspermum, P. paronychia, 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. 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. 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
Synonyms P. douglasii subsp. austiniae
Name authority Greene: Bull. Torrey Bot. Club 8: 99. (1881) Greene: Bull. Calif. Acad. Sci. 1: 212. (1885)
Web links