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.

"/2" is not declared as a valid unit of measurement for this property.

... more about "Polygonum shastense"
reticulate +, tubercled +  and smooth +
exserted +  and included +
dull +  and shiny +
pink +  and purple +
elliptic +  and oblong +
rounded;acute +
Mihai Costea +, François J. Tardif +  and Harold R. Hinds† +
W. H. Brewer +
persistent +  and caducous +
not stipelike +
0.5 cm5 mm <br />0.005 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
lanceolate;elliptic +
coriaceous +
0.2 cm2 mm <br />0.002 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
foliaceous +  and perfoliate +
scale-like +
just below the soil surface or and above the soil surface +  and spreading +
Shasta knotweed +
2-6-flowered +
not reduced +
Calif. +, Nev. +  and Oreg. +
2100-3400 m +
subequal +
adnate +, free +  and distinct +
semi-open +  and open +
disarticulating +  and solid +
decumbent to erect +  and prostrate +
unwinged +  and winged +
black +, red +, brown +  and yellowish +
exserted +  and included +
pubescent +  and glabrous +
spheroidal +, 4-gonous +, lenticular +, biconvex +, discoid +, 3-gonous +  and 2-gonous +
Rocky or gravelly slopes +
compound +, branched +  and simple +
nonmembranous +
articulated +
distributed +
deciduous +
not rugulose +
papillose-denticulate +
swollen +
silvery +, white +  and hyaline +
disintegrating +
deciduous +  and persistent +
0.3 cm3 mm <br />0.003 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
coriaceous +  and membranous +
somewhat larger +
anatropous +, , +  and orthotropous +
accrescent +
0.2 cm2 mm <br />0.002 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
spreading;erect +
greenish white;pink +
campanulate +  and urceolate +
nonaccrescent +
0.5 cm5 mm <br />0.005 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
fleshy +, indurate +  and membranous +
not +  and articulated +
0 cm0 mm <br />0 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
Flowering Jul–Sep. +
(2-)3(-4)-carpellate +
Proc. Amer. Acad. Arts +
papillose-scabridulous +  and smooth +
slender;stout +
woody +  and fibrous +
Illustrated +  and Endemic +
not wiry +  and branched +
zigzagged +  and straight +
prostrate +  and ascending +
papillous-scabridulous +
4-gonous +
5 cm50 mm <br />0.05 m <br /> (40 cm400 mm <br />0.4 m <br />) +
2 +  and 3 +
penicillate +, fimbriate +  and capitate +
deciduous +  and persistent +
2-lobed +  and cylindric +
coriaceous +  and membranous +
connate +  and distinct +
spreading;erect +
Undefined sect. Duravia +  and Polygonum sect. Monticola +
Polygonum shastense +
Polygonum sect. Duravia +
species +
overlapping +
white +  and pink +
connate +  and distinct +
ovate +  and ovate-round +
coriaceous +
persistent +
membranous +
pubescent +  and glabrous +
heterophyllous +  and homophyllous +