Polygonum shastense

W. H. Brewer

Proc. Amer. Acad. Arts 8: 400. 1872.

Common names: Shasta knotweed
IllustratedEndemic
Treatment appears in FNA Volume 5. Treatment on page 563. Mentioned on page 561.
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Subshrubs. Stems prostrate to ascending, brown, branched, gnarled, not wiry, 5–40 cm, glabrous. Leaves ± uniformly distributed, articulated to ocreae, basal leaves caducous or persistent, distal leaves not reduced in size; ocrea 3–5 mm, glabrous, proximal part cylindric, distal part membranous, deciduous with leaves; petiole 0–0.5 mm; blade 1-veined, without pleats, lanceolate to elliptic, 5–25 × 2–5 mm, coriaceous, margins revolute, smooth, apex acute. Inflorescences axillary; cymes in distal axils, 2–6-flowered. Pedicels enclosed in or slightly exserted from ocreae, erect, 2–4 mm. Flowers open or semi-open; perianth 5–9 mm; tube 7–15% of perianth length, tepals partially overlapping, uniformly pink or white, petaloid, ovate to ovate-round, apex rounded; midveins with numerous branched lateral veins; stamens 8. Achenes enclosed in or slightly exserted from perianth, brown, narrowly ovate, 3–4 mm, faces subequal, shiny, smooth.


Phenology: Flowering Jul–Sep.
Habitat: Rocky or gravelly slopes
Elevation: 2100-3400 m

Discussion

Polygonum shastense may be cultivated in rock gardens in rock crevices with favorable water regime and shaded in summer.

Selected References

None.

Lower Taxa

None.
... more about "Polygonum shastense"
Mihai Costea +, François J. Tardif +  and Harold R. Hinds† +
W. H. Brewer +
Shasta knotweed +
Calif. +, Nev. +  and Oreg. +
2100-3400 m +
Rocky or gravelly slopes +
Flowering Jul–Sep. +
Proc. Amer. Acad. Arts +
Illustrated +  and Endemic +
Undefined sect. Duravia +  and Polygonum sect. Monticola +
Polygonum shastense +
Polygonum sect. Duravia +
species +