Polygonum bidwelliae

S. Watson

Proc. Amer. Acad. Arts 14: 294. 1879.

Common names: Bidwell’s knotweed
IllustratedEndemic
Treatment appears in FNA Volume 5. Treatment on page 565. Mentioned on page 561.

Herbs. Stems erect, green, simple or divaricately branched, ± wiry, 2–20 cm, minutely papillose-scabridulous. Leaves crowded at branch tips, not articulated to ocreae, basal leaves caducous or persistent, distal leaves abruptly reduced to bracts; ocrea 8–13 mm, papillose-scabridulous, proximal part cylindric, distal part overlapping and obscuring leaves and flowers, silvery, entire or shallowly dentate; petiole absent; blade 3-veined, without pleats, linear, 5–15(–20) × 0.5–1.5(–2) mm, margins revolute, papillose-denticulate, apex spine-tipped. Inflorescences axillary; cymes in distal axils, 1-flowered. Pedicels absent. Flowers closed; perianth 2–3 mm; tube 10–18% of perianth length; tepals overlapping, pink with pink or white margins, petaloid, elliptic, navicular, apex acute to acuminate; midveins unbranched; stamens 8. Achenes enclosed in perianth at maturity, light brown to brown, ovate-elliptic, 1.8–2.3 mm, faces subequal, shiny, smooth.


Phenology: Flowering May–Jun.
Habitat: Thin volcanic soils, chaparral, montane woodland valleys, grasslands
Elevation: 60-1200 m

Discussion

Polygonum bidwelliae occurs in the Cascade Range and northeastern Sacramento Valley in Butte, Shasta, and Tehama counties.

Selected References

None.

Lower Taxa

None.
... more about "Polygonum bidwelliae"
Mihai Costea +, François J. Tardif +  and Harold R. Hinds† +
S. Watson +
Bidwell’s knotweed +
60-1200 m +
Thin volcanic soils, chaparral, montane woodland valleys, grasslands +
Flowering May–Jun. +
Proc. Amer. Acad. Arts +
Illustrated +  and Endemic +
Undefined sect. Duravia +  and Polygonum sect. Monticola +
Polygonum bidwelliae +
Polygonum sect. Duravia +
species +