Polygonum majus

(Meisner) Piper

Fl. Palouse Reg., 63. 1901.

Common names: Wiry knotweed
Endemic
Basionym: Polygonum coarctatum var. majus Meisner in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 14: 101. 1856
Synonyms: Polygonum douglasii subsp. majus (Meisner) J. C. Hickman
Treatment appears in FNA Volume 5. Treatment on page 570. Mentioned on page 561, 562, 568.

Herbs. Stems erect, green, simple or branched, ± wiry, 15–60 cm, usually papillose-scabridulous. Leaves uniformly distributed, articulated to ocreae, basal leaves often caducous, distal leaves abruptly reduced to bracts, articulated to ocreae; ocrea 5–12 mm, glabrous or papillose-scabridulous, proximal part cylindric, distal part lacerate or disintegrating into fibers; petiole 0.1–2 mm; blade 1-veined, not pleated, linear to narrowly oblong or lanceolate, 15–70 × 2–8 mm, margins revolute, papillose-denticulate, apex acute or mucronate. Inflorescences axillary and terminal, spikelike, elongate; cymes spaced along branches, 2–5-flowered. Pedicels exserted from ocreae, reflexed, 0.5–1 mm. Flowers open or semi-open; perianth (3.5–) 4–5 mm; tube 9–17% of perianth length; tepals overlapping, uniformly white to pink, petaloid, oblong to oblong-obovate, cucullate, navicular in distal 1/4, apex rounded; midveins unbranched or with short lateral branches; stamens 8. Achenes enclosed in perianth, black, elliptic, 3.5–5 mm, faces subequal, shiny or dull, smooth or striate-tubercled.


Phenology: Flowering May–Aug.
Habitat: Dry plains, meadows, sometimes on serpentine
Elevation: 500-2000 m

Distribution

V5 1169-distribution-map.gif

B.C., Calif., Colo., Idaho, Nev., Oreg., Utah, Wash., Wyo.

Discussion

Selected References

None.

Lower Taxa

None.

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

... more about "Polygonum majus"
reticulate +, tubercled +  and smooth +
exserted +  and included +
dull +  and shiny +
3-gonous +, ovate +  and elliptic or lanceolate +
pink +  and purple +
elliptic +  and oblong +
rounded;mucronate;acute +
Mihai Costea +, François J. Tardif +  and Harold R. Hinds† +
(Meisner) Piper +
not stipelike +
Polygonum coarctatum var. majus +
1.5 cm15 mm <br />0.015 m <br /> (7 cm70 mm <br />0.07 m <br />) +
linear;narrowly oblong or lanceolate +
coriaceous +
0.2 cm2 mm <br />0.002 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
foliaceous +  and perfoliate +
scale-like +
just below the soil surface or and above the soil surface +  and spreading +
Wiry knotweed +
2-5-flowered +
B.C. +, Calif. +, Colo. +, Idaho +, Nev. +, Oreg. +, Utah +, Wash. +  and Wyo. +
500-2000 m +
striate-tubercled +  and smooth +
dull +  and shiny +
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 +
Dry plains, meadows, sometimes on serpentine +
compound +, branched +  and simple +
elongate +  and spikelike +
nonmembranous +
articulated +
distributed +
deciduous +
not rugulose +
papillose-denticulate +
with short lateral branches +  and unbranched +
swollen +
silvery +, white +  and hyaline +
disintegrating +
deciduous +  and persistent +
papillose-scabridulous +
0.5 cm5 mm <br />0.005 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
coriaceous +  and membranous +
somewhat larger +
anatropous +, , +  and orthotropous +
accrescent +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
spreading;erect +
0.35 cm3.5 mm <br />0.0035 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
greenish white;pink +
campanulate +  and urceolate +
nonaccrescent +
0.4 cm4 mm <br />0.004 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
fleshy +, indurate +  and membranous +
not +  and articulated +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
Flowering May–Aug. +
(2-)3(-4)-carpellate +
Fl. Palouse Reg., +
papillose-scabridulous +  and smooth +
slender;stout +
woody +  and fibrous +
wiry +, branched +  and simple +
zigzagged +  and straight +
papillose-scabridulous +
4-gonous +
15 cm150 mm <br />0.15 m <br /> (60 cm600 mm <br />0.6 m <br />) +
2 +  and 3 +
penicillate +, fimbriate +  and capitate +
deciduous +  and persistent +
2-lobed +  and cylindric +
coriaceous +  and membranous +
connate +  and distinct +
spreading;erect +
Polygonum douglasii subsp. majus +
Polygonum majus +
Polygonum sect. Duravia +
species +
overlapping +
uniformly white +  and pink +
connate +  and distinct +
navicular +, cucullate +, oblong +  and oblong-obovate +
coriaceous +
persistent +
membranous +
pubescent +  and glabrous +
heterophyllous +  and homophyllous +