Polygonum striatulum

B. L. Robinson

Proc. Boston Soc. Nat. Hist. 31: 263. 1904.

Common names: Texas knotweed
Endemic
Synonyms: Polygonum striatulum var. texense (M. C. Johnston) Costea & Tardif Polygonum texense
Treatment appears in FNA Volume 5. Treatment on page 550. Mentioned on page 547, 548, 549.

Plants perennial, light green, heterophyllous; rhizomes brown, 0.7–3 cm diam. Stems erect to ascending, sparingly branched in distal 1/2, not wiry, 25–60 cm. Leaves: ocrea 6–12 mm, proximal part cylindric, distal part soon disintegrating into brown fibers, later leaving almost no fibrous remains; petiole 0–2 mm; blade light green, linear-lanceolate to oblanceolate, 8–35 × 2–8 mm, margins flat, apex acute or obtuse; stem-leaves 2.1–4 times as long as adjacent branch leaves; distal leaves sharply reduced, not overtopping flowers (shorter than or equaling flowers). Inflorescences axillary and terminal, spikelike; cymes in distal nodes, 2–6-flowered. Pedicels exserted from ocreae, 2–4 mm. Flowers semi-open; perianth 2–3.5 mm; tube 18–25% of perianth length; tepals overlapping, green with white or sometimes pink margins, petaloid, not keeled, oblong to obovate, cucullate; midveins usually unbranched; stamens 7–8. Achenes enclosed in perianth, brown, ovate, 3-gonous, (1.6–) 1.8–2.6 (–3) mm, faces subequal or unequal, apex not beaked, edges concave, shiny, smooth or roughened; late-season achenes common, 4–6 mm.


Phenology: Flowering Dec–Mar or Jun–Oct.
Habitat: Seasonal moist places, sterile prairies, granitic soils
Elevation: 100-700 m

Discussion

Plants with leaves less-conspicuously veined, flowering August to October, and growing in seasonally moist habitats in central and western Texas are recognized by some authors as Polygonum texense or P. striatulum var. texense (M. Costea and F. J. Tardif 2003).

Selected References

None.

Lower Taxa

None.

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

... more about "Polygonum striatulum"
0.26 cm2.6 mm <br />0.0026 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
exserted +  and included +
dull +  and shiny +
smooth;roughened +
3-gonous +  and ovate +
whitish yellow +
elliptic +  and oblong +
obtuse;acute +
Mihai Costea +, François J. Tardif +  and Harold R. Hinds† +
B. L. Robinson +
not stipelike +
light green +
0.8 cm8 mm <br />0.008 m <br /> (3.5 cm35 mm <br />0.035 m <br />) +
linear-lanceolate;oblanceolate +
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 +
Texas knotweed +
2-6-flowered +
roughened +  and smooth +
concave +
100-700 m +
unequal +  and subequal +
adnate +, free +  and distinct +
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 +
Seasonal moist places, sterile prairies, granitic soils +
compound +, branched +  and simple +
nonmembranous +
0.4 cm4 mm <br />0.004 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
sessile +  and petiolate +
deciduous +
pink +  and white +
pubescent +  and glabrous +
lobed +, undulate +, crisped +, crenulate +  and entire +
swollen +
silvery +, white +  and hyaline +
disintegrating +
deciduous +  and persistent +
0.6 cm6 mm <br />0.006 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
coriaceous +  and membranous +
somewhat larger +
anatropous +, , +  and orthotropous +
erect;spreading +
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 +
0.2 cm2 mm <br />0.002 m <br /> (0.35 cm3.5 mm <br />0.0035 m <br />) +
fleshy +, indurate +  and membranous +
0 cm0 mm <br />0 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
Flowering Dec–Mar or Jun–Oct. +
(2-)3(-4)-carpellate +
Proc. Boston Soc. Nat. Hist. +
0.7 cm7 mm <br />0.007 m <br /> (3 cm30 mm <br />0.03 m <br />) +
slender;stout +
woody +  and fibrous +
7 +  and 8 +
2.1-4 times as long as adjacent branch leaves +
not wiry +  and branched +
straight +
erect +  and ascending +
papillous-scabridulous +
25 cm250 mm <br />0.25 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 striatulum var. texense +  and Polygonum texense +
Polygonum striatulum +
Polygonum sect. Polygonum +
species +
overlapping +
connate +  and distinct +
cucullate +, oblong +  and obovate +
coriaceous +
persistent +
membranous +
pubescent +  and glabrous +
not cushionlike +