Polygonella fimbriata
Polygonella
sandhill jointweed
jointweed, polygonelle, wireweed
erect, simple or sparingly branched proximally, scabrous or, sometimes, glabrous proximally.
erect, decumbent, or prostrate, glabrous or scabrous.
adnate to stems, appearing to arise internodally.
persistent;
ocrea margins ciliate;
blade linear to falcate, (10–)19–36(–50) × (0.6–)1–1.5(–3) mm, base tapered, margins not hyaline, apex acuminate, minutely scabrous.
deciduous or, rarely, with leaves persisting more than 1 year, sometimes fugacious, cauline, alternate;
ocrea usually persistent, sometimes disintegrating with age and deciduous distally, chartaceous or coriaceous;
petiole apparently absent, articulate basally;
blade filiform to broadly obovate, margins entire.
(5–)10–24(–30) mm;
ocreola encircling rachis, only the base adnate to rachis, apex acuminate.
terminal, racemelike, pedunculate.
spreading in anthesis and fruit, 0.1–0.7 mm, as long as or much longer than subtending ocreola.
present.
bisexual or some pistillate, these usually distal;
outer tepals loosely appressed in anthesis and fruit, pink with white margins, often drying orange, ovate, 1.1–2.3 mm in anthesis, margins erose;
inner and transitional tepals loosely appressed in anthesis and fruit, pink with white margins, often drying orange, oblong, 1.2–2.2 mm in anthesis, margins deeply fringed;
filaments monomorphic;
anthers pink;
styles and stigmas 0.6–1.3 mm in anthesis.
bisexual, or some or all functionally unisexual, 1 per ocreate fascicle, base stipelike;
perianth nonaccrescent, white, pink, red, greenish, or yellowish, campanulate, glabrous;
tepals 5, distinct, petaloid, dimorphic, in 2 whorls with 2 outer and 3 inner or 2 outer and 2 inner plus 1 transitional;
stamens 8, in 2 series with 5 outer and 3 inner;
filaments distinct, free, dilated proximally, dimorphic, inner 3 dilated more abruptly than outer 5, with toothed or horned shoulders, or monomorphic (in P. fimbriata and P. robusta), glabrous (pubescent basally in P. basiramia);
anthers white, yellow, orange, pink, or dark red, elliptic to ovate or round;
styles (2–)3, erect, distinct;
stigmas (2–)3, capitate.
included or exserted, yellow-brown, 3-gonous, 1.5–2.5 × 1–1.5 mm, shiny and smooth proximally, dull to shiny and minutely roughened distally.
included or exserted, yellow-brown, brown, or reddish brown, wingless or narrowly winged, (2–)3(–4)-gonous, glabrous.
embryo straight or slightly curved.
= 11.
Polygonella fimbriata
Polygonella
The chromosome number of 2n = 32 listed for Polygonella fimbriata by P. O. Lewis and D. J. Crawford (1995) appears to be in error. They cited J. H. Horton (1963) as the source; Horton did not count this species.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Species 11 (11 in flora).
Polygonella is distinct from other genera of Polygonaceae in having branches adnate to the stem and thus appearing to arise internodally. Palynological, anatomical, and morphological evidence suggests Polygonella is closely related to Polygonum sect. Duravia (L.-P. Ronse Decraene et al. 2004; Hong S. P. et al. 1998; P. O. Lewis 1991).
Within-population allozyme diversity is lower in the two most widespread species of the genus as compared to their narrowly endemic congeners (P. O. Lewis and D. J. Crawford 1995). High levels of selfing or depletion of diversity due to Pleistocene glaciation have been suggested as possible explanations for the lower allozyme diversity within populations of Polygonella americana and P. articulata.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Margins of inner tepal deeply fringed; filaments of stamens monomorphic | → 2 |
1. Margins of inner tepal entire to erose; filaments of stamens dimorphic | → 3 |
2. Margins of leaf blade not hyaline; stems scabrous or, sometimes, glabrous proximally | P. fimbriata |
2. Margins of leaf blade hyaline; stems glabrous or sparingly scabrous on angles distally | P. robusta |
3. Ocreae margins ciliate | → 4 |
3. Ocreae margins not ciliate | → 6 |
4. Ocreolae not encircling rachis of raceme, their sides and bases adnate to rachis; inflorescences 2-6(-8) mm; outer tepals 0.5-0.9 mm in anthesis | P. parksii |
4. Ocreolae encircling rachis of raceme, only their bases adnate to rachis; inflorescences 10-45 mm; outer tepals 0.7-1.5 mm in anthesis | → 5 |
5. Stems branched at or below ground level | P. basiramia |
5. Stems simple, sometimes branched distally, if present, well above ground | P. ciliata |
6. Leaf blades (3-)9-30 mm wide, oblanceolate to obovate or broadly spatulate | P. macrophylla |
6. Leaf blades 0.3-6(-8) mm wide, filiform to broadly spatulate | → 7 |
7. Styles and stigmas 0.4-1 mm in anthesis; plants perennial | → 8 |
7. Styles and stigmas ca. 0.1 mm or less in anthesis; plants annual or perennial | → 9 |
8. Stems erect; outer tepals sharply reflexed early in anthesis and in fruit | P. americana |
8. Stems prostrate; outer tepals loosely appressed in anthesis, sometimes spreading in fruit | P. myriophylla |
9. Plants perennial; margins of leaf blade hyaline at least along distal 1/ 2; outer tepals usually reflexed in fruit | P. polygama |
9. Plants annual; margins of leaf blade not hyaline; outer tepals loosely appressed to spreading in fruit | → 10 |
10. Pedicels 0.9-3 mm, longer than subtending ocreolae; leaf blades 0.4-1.2 mm wide | P. articulata |
10. Pedicles 0.1-0.3 mm, as long as subtending ocreolae; leaf blades 0.8-5(-8) mm wide | P. gracilis |
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