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Polygonum ramosissimum subsp. ramosissimum

Higher Taxonomy
Family: PolygonaceaeView DescriptionDichotomous Key
Habit: 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.
Genera In Family: 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. Note: 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.
eFlora Treatment Author: Mihai Costea, except as noted
Scientific Editor: Thomas J. Rosatti, Bruce G. Baldwin.
Genus: PolygonumView DescriptionDichotomous Key

Common Name: KNOTWEED
Habit: 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.
Etymology: (Greek: poly, many, gony, knee joint, or gone, seed, of uncertain meaning) Note: 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.
eFlora Treatment Author: Mihai Costea
Reference: Costea 2005 Brittonia 57:1--27
Species: Polygonum ramosissimumView Description 

Habit: Annual. Stem: erect, 10--100(200) cm, glabrous, green, ribbed, branches generally profuse in distal 1/2. Leaf: proximal often early-deciduous, distal < to >> flowers; ocreae 6--12(15) mm, proximally cylindric, distally soon disintegrating to brown fibers; petiole 2--4 mm; blade 8--70 mm, 4--18(35) mm wide, narrowly elliptic, lanceolate, or oblanceolate (ovate), light-yellow-green to -blue-green, margins flat, tip acute to acuminate or obtuse. Inflorescence: axillary, terminal, spike-like; pedicels included or exserted, 1--6 mm; flowers 2--5, crowded distally or not. Flower: closed; perianth (2)2.2--3.6(4) mm, green-yellow, margin green-yellow to yellow or white to pink, tube 20--38% of length, lobes overlapped, not keeled, elliptic to oblong, hood-shaped, midvein thickened or not; stamens 3--6(8). Fruit: included or exserted, 1.6--3.5 mm, ovate, dark-brown, shiny or dull, rough to generally smooth; late-season common, 4--15 mm. Chromosomes: 2n=60.
Note: An unnamed variant of Polygonum ramosissimum in saline marshes in SnFrB mistakenly identified as Polygonum patulum M. Bieb., may be taxonomically significant; study needed.
Polygonum ramosissimum Michx. subsp. ramosissimum
Habit: Plant generally yellow-green fresh or dry. Stem: 30--200 cm. Leaf: distal 1--2 mm, < flowers, or 5--15 mm, >> flowers; blade 35--70 mm, 7--18(35) mm wide, narrowly elliptic to lanceolate (ovate), tip acute to acuminate; stem leaves 2.1--3.5(4.2) × branch leaves. Inflorescence: axillary, terminal, spike-like; pedicels exserted, 2.5--6 mm; flowers 2--5, crowded distally. Flower: perianth (2.6)3--4 mm, margin green-yellow, yellow (white or pink); stamens 3--6(8). Fruit: (2.3)2.5--3.5 mm, shiny or dull, smooth to rough; late-season common, 5--12 mm.
Ecology: Disturbed places, saline marshes; Elevation: < 200 m. Bioregional Distribution: n CA-FP, SnFrB; Distribution Outside California: North America. Flowering Time: Jul--Sep
Synonyms: Polygonum exsertum Small; Polygonum interior Brenckle; Polygonum latum Rydb.; Polygonum leptocarpum B.L. Rob.; Polygonum stevensii Brenckle; Polygonum triangulum E.P. Bicknell
Jepson eFlora Author: Mihai Costea
Reference: Costea 2005 Brittonia 57:1--27
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)

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Botanical illustration including Polygonum ramosissimum subsp. ramosissimumbotanical illustration including Polygonum ramosissimum subsp. ramosissimum

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Citation for this treatment: Mihai Costea 2012, Polygonum ramosissimum subsp. ramosissimum, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on July 17, 2024.

Citation for the whole project: Jepson Flora Project (eds.) 2024, Jepson eFlora,, accessed on July 17, 2024.

No expert verified images found for Polygonum ramosissimum subsp. ramosissimum.

Geographic subdivisions for Polygonum ramosissimum subsp. ramosissimum:
n CA-FP, SnFrB
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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 occurrence).


Data provided by the participants of the  Consortium of California Herbaria.

View all CCH records
All markers link to CCH specimen records. The original determination is shown in the popup window.
Blue markers indicate specimens that map to one of the expected Jepson geographic subdivisions (see left map). Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.

CCH collections by month Flowering-Fruiting Monthly Counts

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa, if there are more than 1 infraspecific taxon in CA.
Blue line denotes eFlora flowering time (fruiting time in some monocot genera).