Oriental lady's thumb
Persicaria longiseta (Bruijn) Kitagawa


Persicaria longiseta is an annual forb that can reach 6-30 in. (15.2-76.2 cm) in height and can be either erect or sprawling.
Leaves are elongate, narrow and pointed at the base and tip. Stems have swollen nodes with papery sheaths (ocrea). Ocrea have long, hair-like bristles on the margin.
Flowering occurs from June to October, when pink flowers develop at the apex of the stems. Flowers are 0.13 in. (0.3 cm) long and occur in groups.
Seeds are smooth, dark colored, dry, and 3 angled.
Ecological Threat
Persicaria longiseta is native to Asia and occurs in disturbed habitats such as along roadsides and in pastures. Plants also inhabit wet areas.


Selected Images


EDDMapS Distribution

EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit www.eddmaps.org

State Regulated List

State Regulated List - This map identifies those states that list this species on their regulated list. For more information, visit Invasive.org

Taxonomic Rank

Kingdom: Plantae
Phylum: Magnoliophyta
Class: Magnoliopsida
Subclass: Caryophyllidae
Order: Polygonales
Family: Polygonaceae
Genus: Persicaria
Subject: Persicaria longiseta (Bruijn) Kitagawa

Synonyms and Other Names

Other Common Names:
Asiatic smartweed, bristled knotweed, bunchy knotweed

Related Scientific Names:
Polygonum cespitosum var. longisetum (Bruijn) Danser (Misspelling)
Persicaria cespitosum var. longisetum (Bruijn) A.N. Steward (Synonym)
Persicaria longisetum Bruijn (Synonym)
Polygonum cespitosum var. longisetum (Bruijn) A.N. Steward (Synonym)


Plants - Forbs/Herbs