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Previous taxon Indexes to all accepted names and synonyms:
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Mihai Costea, except as noted

Annual to shrub [tree]. Stem: nodes swollen or not. Leaf: simple, basal or cauline, generally alternate; ocreae present or 0, generally scarious, persistent or not. Inflorescence: flower clusters in axillary to terminal cyme-, panicle-, raceme-, spike-, umbel- or head-like arrangements, entire inflorescence or main inflorescence branches generally subtended by bracts ("inflorescence bracts"); peduncles present or 0; flower clusters in Eriogoneae-Eriogonoideae subtended by involucre of >= 1 free or ± fused, sometimes awn-tipped bracts ("involucre bracts") or, in Polygonoideae and rarely in Eriogonoideae, not (if bracts completely fused, involucre "tubular"); pedicels in Eriogoneae each often subtended by 2 free, transparent, linear bractlets or in Polygonoideae all subtended by 2+ fused, membranous, wide bractlets. Flower: generally bisexual, small, 1–200 per node; perianth parts 2–6, generally in 2 whorls, free or basally fused, generally petal-like, often ± concave adaxially, often darker at midvein, often turning ± red or ± brown in age; stamens [1]3 or 6–9 in 2 whorls; ovary superior, 1-chambered, ovule 1, styles 1–3. Fruit: achenes, included in or exserted from perianth, generally 3-angled, ovoid or elliptic, generally glabrous.
48 genera, ± 1200 species: worldwide, especially northern temperate; some cultivated for food (Coccoloba, sea-grape; Fagopyrum, Rheum, Rumex) or ornamental (Antigonon, lovechain; Coccoloba; Muehlenbeckia; Persicaria; Polygonum), a few timbered (Coccoloba; Triplaris). Several (Emex; Fallopia; Persicaria; Polygonum; Rumex) are weeds. [Freeman & Reveal 2005 FNANM 5:216–601] Treatment of genera in Eriogonoideae based on monographic work of James L. Reveal. Involucre number throughout is number (1–many) per ultimate grouping, at tips of ultimate branches; flower number is per flower cluster or involucre, unless otherwise stated. Fagopyrum esculentum Moench not naturalized, considered an historical waif (or garden weed ± presently), therefore not treated. Scientific Editors: Thomas J. Rosatti, Bruce G. Baldwin.

Key to Polygonaceae

Annual, perennial herb to shrub. Stem: prostrate to erect, 8–16-ribbed or 4–5-angled with ribs 0 or obscure; glabrous or papillate-scabrous. Leaf: cauline, alternate, petioled or not; ocrea generally jointed to leaf, generally cylindric proximally, generally translucent distally, white or silvery, 2-lobed, glabrous, disintegrating to fibers or completely; blade linear, lanceolate, elliptic, ovate, or subround, entire. Inflorescence: axillary, terminal, generally spike-like; peduncle 0; pedicels present or 0, included in to exserted from bractlets; flowers 1–7(10). Flower: bisexual, base not stalk-like; perianth not enlarging, bell- to urn-shaped, glabrous, white or green-white to pink; perianth parts 5, fused 3–60[70]%, petal- or sepal-like, similar [or not], outer ± keeled or not, < to > inner, midveins generally a different shade or color than rest of perianth; stamens 3–8 (some staminodes or not), filaments or at least innermost free, wider at base, fused to perianth tube or not, anthers elliptic to oblong, white-yellow or generally pink to purple (orange-pink); styles (2)3, generally spreading, free or fused basally, stigmas 2–3, head-like. Fruit: included or exserted, wings 0, angles (2)3, 1 face much narrower than other (1)2 or not; tip beak-like, yellow-green, brown, or black. Seed: embryo curved.
± 65 species: ± worldwide; sect. Duravia restricted to western North America. (Greek: many, knee joint or seed, of uncertain meaning) [Costea 2005 Brittonia 57:1–27] Many species of sect. Polygonum with 2 kinds of fruit, differing in germination and morphology (summer fruit brown, ovate, tubercled to smooth; late-season fruit olive-green, lanceolate, smooth, 2–5 × > summer), but of little taxonomic importance. Mature, early-season plants with leaves, flowers, fruits needed for identification. Flowers "closed" or "1/2-open" should be determined on herbarium specimens. Other taxa in TJM (1993) moved to Aconogonon, Bistorta, Fallopia, Persicaria.
Unabridged etymology: (Greek: poly, many, gony, knee joint, or gone, seed, of uncertain meaning)

Key to Polygonum

P. polygaloides Meisn. POLYGALA KNOTWEED
Annual. Stem: erect, (2)6–20(25) cm, ± wiry, glabrous, green, ± angled, branches generally widely spreading (0). Leaf: basal leaves early-deciduous, distal abruptly reduced to bracts; ocreae 4–8 mm, glabrous, proximally cylindric, distally cut; petiole 0; blade 10–40 mm, 1–2.5 mm wide, narrowly linear, margin rolled under, smooth, tip acute or mucronate. Inflorescence: axillary, terminal, spike-like, ± spheric to cylindric; pedicels included, erect, 0–2 mm; flowers 1–3, in most axils or crowded distally. Flower: generally closed; perianth 1.5–3 mm, white to red, tube 19–40% of length, lobes overlapped, lance-oblong, ± keeled, tip acute to acuminate, midvein thickened, branches 2, proximal, or generally 0; stamens 3–8. Fruit: included, 1.3–2.5 mm, ovate to lanceolate, light-yellow or light- or green- to dark-brown, shiny or dull, smooth or net-like with longitudinal ridges. Highly variable; intermediates occur between all subspecies except Polygonum polygaloides subsp. polygaloides, of northwestern United States (except California), Alberta. [Online Interchange]
Unabridged note: Alternatively, Polygonum polygaloides could be recognized in narrow sense, without infraspecific taxa, and the 3 subspecies in California could be treated as subspecies of a separate Polygonum kelloggii (earliest available name).

P. polygaloides subsp. confertiflorum (Piper) J.C. Hickman
Stem: 2–15 mm. Inflorescence: generally distal, rarely also continuous from stem bases, 7–40 mm, 5–10 mm wide, ovoid to cylindric; bracts ascending to appressed, 4–11 mm, linear to lance-linear, ± rigid, margin rolled under, white, scarious border 0.25–0.4 mm wide, midvein ± heavily thickened, branches obscure. Flower: perianth 1.8–2.2(2.4) mm, white or red, tube 22–30% of length, tube and base of lobes smooth or papillate; stamens 3. Fruit: 1.3–2.1 mm, lance-ovate to ovate, brown to dark-brown, dull, net-like with longitudinal ridges.
Vernal pools, wet meadows; 500–1900 m. Northwestern California, Cascade Range, n Sierra Nevada, Modoc Plateau; to Saskatchewan, Montana, Wyoming. May–Aug [Online Interchange]

Previous taxon: Polygonum polygaloides
Next taxon: Polygonum polygaloides subsp. esotericum


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Citation for the whole project: Jepson Flora Project (eds.) 2013. Jepson eFlora,, accessed on Mar 27 2015
Citation for this treatment: [Author of taxon treatment] 2013. Polygonum, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on Mar 27 2015

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Geographic subdivisions indicated for the distribution of Polygonum polygaloides subsp. confertiflorum Markers link to CCH specimen records. If the markers are obscured, reload the page [or change window size and reload]. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.
map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).

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Data provided by the participants of the Consortium of California Herbaria.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.