Polygonum parryi |
Polygonum utahense |
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Parry's knotweed, Parry's or prickly knotweed, prickly knotweed |
Utah knotweed |
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Habit | Herbs, compact, often cushion-like. | Herbs. |
Stems | erect, green-brown, simple or branched from base, not wiry, 2–5(–8) cm, glabrous. |
erect, green, simple or with few branches, not wiry, 1.5–3.5 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; ocrea 2–3.5 mm, papillose-scabridulous, proximal part funnelform, distal part hyaline, lacerate; petiole absent; blade 1-veined, not pleated, linear-subulate, 6–14 × 1 mm, coriaceous, margins revolute, touching along midrib, apex acute, mucronate, papillose. |
Inflorescences | axillary; cymes in most axils, 1-flowered. |
axillary and terminal, spikelike, dense; cymes overlapping, starting almost from stem base, 2–4-flowered. |
Pedicels | absent. |
enclosed in ocreae, erect to spreading, 0.4–1 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. |
open; perianth 2–2.5 mm; tube 20–25% of perianth length; tepals overlapping, uniformly white, petaloid, oblong to widely obovate, cucullate, navicular in distal 1/4, apex rounded; midveins branched; 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, 1.5–2 mm, faces subequal, shiny, smooth. |
Polygonum parryi |
Polygonum utahense |
|
Phenology | Flowering May–July. | Flowering Jul–Sep. |
Habitat | Vernally moist, open, sandy or rocky places | Dry, sandy ravines, rocky Navajo sandstone spur |
Elevation | 500-2000 m (1600-6600 ft) | 2300 m (7500 ft) |
Distribution |
CA; WA
|
UT |
Discussion | Polygonum utahense has been treated as a synonym of P. sawatchense by some authors (e.g., S. L. Welsh et al. 1987; J. T. Kartesz and C. A. Meacham 1999). Its perianth morphology suggests a relationship with P. cascadense, from which it differs in its dwarf habit and uniformly papillose leaves with margins revolute, touching along midribs. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|
Source | FNA vol. 5, p. 563. | FNA vol. 5, p. 571. |
Parent taxa | Polygonaceae > subfam. Polygonoideae > Polygonum > sect. Duravia | Polygonaceae > subfam. Polygonoideae > Polygonum > sect. Duravia |
Sibling taxa | ||
Synonyms | P. douglasii var. utahense | |
Name authority | Greene: Bull. Torrey Bot. Club 8: 99. (1881) | Brenckle & Cottam: Bull. Univ. Utah, Biol. Ser. 4(4): 3, plate 1. (1940) |
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