Polygonum heterosepalum

M. Peck & Ownbey

Madroño 10: 250. 1950.

Common names: Dwarf desert knotweed
EndemicConservation concern
Treatment appears in FNA Volume 5. Treatment on page 563. Mentioned on page 548, 561, 562.

Herbs, compact, often cushionlike. Stems erect, green or reddish, simple or branched near base, not wiry, 1.5–5 cm, glabrous. Leaves uniformly distributed, dense, not articulated to ocreae, basal leaves persistent or caducous, distal leaves gradually reduced to bracts; ocrea 3–6 mm, glabrous, proximal part cylindric, distal part disintegrating almost to base, with whitish, straight, rigid fibers; petiole absent; blade 3-veined, without pleats, linear to lanceolate, 10–20 × 0.6–2.7 mm, margins revolute, smooth, apex spine-tipped. Inflorescences axillary; cymes in most axils, 2–3-flowered. Pedicels enclosed in ocreae, erect, 0.1–1 mm. Flowers closed; perianth 2.3–2.7 mm; tube 3–7% of perianth length; tepals overlapping, whitish with whitish or pink margins, petaloid, oblong, navicular, dimorphic, outer 2 shorter than inner 3, outer 2 0.8–1.2 mm, inner 2.3–2.7 mm, papillose at base, apex acute or acuminate; midveins unbranched; stamens 5–6. Achenes enclosed in perianth, olive brown, narrowly ovate to ovatelanceolate, 1.5–2 mm, faces subequal, shiny, smooth.


Phenology: Flowering Jun–Aug.
Habitat: Dry waste ground, open flats in sagebrush plains, ponderosa pine forests
Elevation: 1000-1500 m

Discussion

Of conservation concern.

Selected References

None.

Lower Taxa

None.

"/2" is not declared as a valid unit of measurement for this property."-1.2mm" is not declared as a valid unit of measurement for this property.

... more about "Polygonum heterosepalum"
reticulate +, tubercled +  and smooth +
olive brown +
exserted +  and included +
dull +  and shiny +
narrowly ovate +  and ovatelanceolate +
pink +  and purple +
elliptic +  and oblong +
acuminate;acute +
Mihai Costea +, François J. Tardif +  and Harold R. Hinds† +
M. Peck & Ownbey +
caducous +  and persistent +
not stipelike +
1 cm10 mm <br />0.01 m <br /> (2 cm20 mm <br />0.02 m <br />) +
linear;lanceolate +
coriaceous +
0.06 cm0.6 mm <br />6.0e-4 m <br /> (0.27 cm2.7 mm <br />0.0027 m <br />) +
foliaceous +  and perfoliate +
scale-like +
just below the soil surface or and above the soil surface +  and spreading +
Dwarf desert knotweed +
2-3-flowered +
Idaho +, Nev. +  and Oreg. +
1000-1500 m +
subequal +
straight +
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 +
Dry waste ground, open flats in sagebrush plains, ponderosa pine forests +
compound +, branched +  and simple +
0.23 cm2.3 mm <br />0.0023 m <br /> (0.27 cm2.7 mm <br />0.0027 m <br />) +
nonmembranous +
not articulated +
distributed +
deciduous +
pink +  and whitish +
not rugulose +
papillose-denticulate +
swollen +
silvery +, white +  and hyaline +
disintegrating +
deciduous +  and persistent +
0.3 cm3 mm <br />0.003 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
coriaceous +  and membranous +
somewhat larger +
anatropous +, , +  and orthotropous +
accrescent +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
spreading;erect +
greenish white;pink +
campanulate +  and urceolate +
nonaccrescent +
0.23 cm2.3 mm <br />0.0023 m <br /> (0.27 cm2.7 mm <br />0.0027 m <br />) +
fleshy +, indurate +  and membranous +
not +  and articulated +
Flowering Jun–Aug. +
(2-)3(-4)-carpellate +
papillose-scabridulous +  and smooth +
slender;stout +
woody +  and fibrous +
Endemic +  and Conservation concern +
5 +  and 6 +
not wiry +, branched +  and simple +
reddish +  and green +
zigzagged +  and straight +
papillous-scabridulous +
4-gonous +
1.5 cm15 mm <br />0.015 m <br /> (5 cm50 mm <br />0.05 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 heterosepalum +
Polygonum sect. Duravia +
species +
overlapping +
connate +  and distinct +
navicular +  and oblong +
coriaceous +
persistent +
membranous +
pubescent +  and glabrous +
heterophyllous +  and homophyllous +