Reynoutria japonica

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Distribution Map: Based on vouchered plant specimens only. View county names by placing the mouse cursor over a particular county.

Family:POLYGONACEAE
Species:Reynoutria japonica Houtt.
Common Name:Japanese Knotweed; Japanese Bamboo; Japanese Buckwheat
Habitat:Escaped from cultivation and naturalized in urban forests, roadsides, and other altered habitats.
Associated Ecological Communities:**
Growth Habit:Herb
Duration:Perennial
Category:Vascular
USDA Symbol:**
Plant Notes:Japanese Knotweed is an introduced herbaceous perennial in the Buckwheat family (Polygonaceae). It is native to China, Japan, Korea, Taiwan, and Russia. In Alabama it has been collected from scattered areas across the state. Japanese Knotweed occurs on roadsides and railroad margins, along ditches and streams, in the margins of fields and pastures, on urban lots, and in other disturbed areas. It is a perennial from thick rhizomes. Stems are erect, 3-6 feet in height, usually branched above the middle, striate, papillate, and often red spotted. Leaves are alternate, deciduous, petiolate, ovate to elliptic in outline, glabrous, and with entire margins. Flowers are produced in axillary panicles. Flowers are either bisexual or unisexual (pistillate). The perianth is white or greenish, campanulate, glabrous, with 5 petal-like tepals and 6-8 stamens. The three outer tepals are larger and winged. The fruit is an achene. Japanese Knotweed was introduced as an ornamental in the 1860’s. It is an aggressive weed, forming extensive colonies that exclude native vegetation. It has also been planted as a nectar source for bees and to reclaim strip mined sites. Once established it is difficult to eradicate. It is listed as a noxious weed in Alabama, California, Oregon, Vermont, and Washington.—A. Diamond.
Taxonomic Notes:**
Status:Not Native
References:**
Specimen: View specimen details in the Alabama Herbarium Consortium Specimen Database

** Not applicable or data not available.

Classification

FamilyPOLYGONACEAE - Buckwheat family
Genus Reynoutria
Species Reynoutria japonica Houtt. - Japanese Knotweed; Japanese Bamboo; Japanese Buckwheat

Citation

Citation Reynoutria japonica Houttuyn, Nat. Hist. 2(8): 640, t. 51, f. 1. 1777.
Basionym: **
Type: JAPAN:

** Not applicable or data not available.

Synonyms

SynonymFull CitationBasionymType
Fallopia japonica    
Pleuropterus zuccarinii    
Polygonum cuspidatum    

Specimens and Distribution

This species has been reported in the following counties by the herbaria listed. An overview of the individual specimens are provided in the table that follows. Click on the accession number to view details; click on column headers to sort; choose a county or herbaria to filter the specimen data.

Counties included on distribution map: Autauga, Calhoun, Clay, Colbert, Etowah, Hale, Houston, Jefferson, Randolph

Counties represented by specimen data listed below:

Herbaria represented by specimen data listed below: ALNHS, AUA, JSU, SAMF, TROY, UNA, UWAL

Range of years during which specimens were collected: 1998 - 1998

Barcode / Accession No.
County
Coll. Date
Collector &
Collection No.
Herbarium &
Herbarium Name Used
Image
TROY000040862 Autauga 21 Apr 2012 Keener, Brian R.
7153		 TROY
Reynoutria japonica Houttuyn
UWAL0011884 Autauga 21 Apr 2012 Keener, Brian R.
7153		 UWAL
Reynoutria japonica Houttuyn
ALNHS00004106 Autauga 08 Jul 2016 Taylor, Chris T.
SP#2411		 ALNHS
Reynoutria japonica Houtt.
TROY000046599 Autauga 02 May 2017 Parker, Matthew R.
713		 TROY
Reynoutria japonica Houttuyn
UWAL0046691 Autauga 02 May 2017 Parker, Matthew R.
713		 UWAL
Reynoutria japonica Houttuyn
UWAL0034213 Calhoun 28 May 2015 Spaulding, Daniel D.
14278		 UWAL
Reynoutria japonica Houtt
AUA000033338 Calhoun 28 May 2015 SPAULDING, DANIEL D.
14278		 AUA
REYNOUTRIA JAPONICA HOUTT.
AUA000041104 Calhoun 28 May 2015 SPAULDING, DANIEL D.
14278		 AUA
REYNOUTRIA JAPONICA HOUTT.
UNA00072254 Calhoun 28 May 2015 Spaulding, Daniel D.
14278		 UNA
Reynoutria japonica Houtt.
SAMF0007129 Calhoun 28 May 2015 Spaulding, Daniel D.
14278		 SAMF
Reynoutria japonica Houttuyn
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