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Fallopia sachalinensis
GIANT KNOTWEED


Higher Taxonomy
Family: PolygonaceaeView DescriptionDichotomous Key
Common Name: BUCKWHEAT FAMILY
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: FallopiaView DescriptionDichotomous Key


Habit: Annual, perennial herb, vine or not. Stem: erect, trailing, or twining, glabrous or hairy, ribs 0. Leaf: cauline, alternate, petioled; ocrea persistent or not, cylindric, papery, opaque; blade broad-ovate to triangular, entire. Inflorescence: axillary, terminal, spike-, panicle-, or raceme-like; flowers 3--7; peduncle present or 0. Flower: bisexual or pistillate (1 kind per pl); perianth generally enlarging, bell-shaped, pale green or white to pink, glabrous, base stalk-like, parts 5, fused basally or +- completely, of 2 kinds, outer 3 generally winged, > inner 2; stamens 6--8, filaments free, wider basally, glabrous or hairy, anthers yellow to pink or red, ovate to elliptic; styles 3, spreading, fused basally or +- completely, stigmas head-like, fringed, or peltate. Fruit: included or exserted, 3-angled, brown to black. Seed: embryo straight.
Etymology: (for Gabriele Fallopio, 1523--1562, Italian professor of anatomy, botany, and surgery, for whom Fallopian tubes also named)
eFlora Treatment Author: Mihai Costea
Fallopia sachalinensis (F. Schmidt) Ronse Decr.
NATURALIZED
Habit: Perennial herb, rhizomed. Stem: generally in dense clumps, erect, 2--4(5) m, glabrous, branches few. Leaf: ocrea 6--12 mm, +- brown, margins oblique, glabrous or puberulent; blade 15--30(40) cm, 7--25 cm wide, ovate-oblong, abaxially minute-dotted, with many-celled hairs 0.2--0.6 mm on veins, adaxially glabrous, base cordate, tip acute to acuminate. Inflorescence: axillary, generally distal, erect or spreading, panicle-like, 3--8 cm; peduncle 0--4 cm; pedicels 2--4 mm, glabrous; flowers 4--7. Flower: bisexual or functionally +- unisexual; perianth 4.5--6.5 mm, +- green, glabrous, lobes obovate to elliptic, tips obtuse to acute; stamens 6--8, filaments glabrous; styles fused basally, stigmas fringed. Fruit: included, 2.8--4.5 mm, 1.1--1.8 mm wide, brown, shiny, smooth. Chromosomes: 2n=44,66,102,132.
Ecology: Disturbed places; Elevation: < 500 m. Bioregional Distribution: NCo, SnFrB, SCo, expected elsewhere; Distribution Outside California: native to central Asia. Flowering Time: Aug--Sep Note: Introduced as ornamental, spreading aggressively; hybrids with Fallopia japonica (Fallopia ×bohemica (Chrtek & Chrtková) J.P. Bailey), intermediate in leaf shape, size, potentially spreading vegetatively.
Synonyms: Polygonum sachalinense F. Schmidt; Reynoutria sachalinensis (F. Schmidt) Nakai; Tiniaria sachalinensis (F. Schmidt) Janchen
Jepson eFlora Author: Mihai Costea
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)
Noxious Weed listed on the CDFA Weed Pest Ratings table
View the CDFA Pest Rating page for Fallopia sachalinensis
Weed listed by Cal-IPC

Previous taxon: Fallopia japonica
Next taxon: Gilmania

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Botanical illustration including Fallopia sachalinensis

botanical illustration including Fallopia sachalinensis

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Citation for this treatment: Mihai Costea 2012, Fallopia sachalinensis, in Jepson Flora Project (eds.) Jepson eFlora, https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=82465, accessed on April 18, 2024.

Citation for the whole project: Jepson Flora Project (eds.) 2024, Jepson eFlora, https://ucjeps.berkeley.edu/eflora/, accessed on April 18, 2024.

No expert verified images found for Fallopia sachalinensis.



Geographic subdivisions for Fallopia sachalinensis:
NCo, SnFrB, SCo, expected elsewhere
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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 occurence).





 

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

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).