Persicaria longiseta

Persicaria longiseta
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Core eudicots
Order: Caryophyllales
Family: Polygonaceae
Genus: Persicaria
Species: P. longiseta
Binomial name
Persicaria longiseta
(Bruijn) Kitagawa 1937
Synonyms[1]
  • Polygonum cespitosum var. longisetum (Bruijn) C.F.Reed 1987
  • Polygonum longisetum Bruijn 1854
  • Polygonum caespitosum var. longisetum (Bruijn) Danser
  • Polygonum cespitosum var. longisetum (Bruijn) Steward

Persicaria longiseta is a species of flowering plant in the knotweed family known by the common names Oriental lady's thumb, bristly lady's thumb, Asiatic smartweed, long-bristled smartweed, Asiatic waterpepper, bristled knotweed, bunchy knotweed, and tufted knotweed. It is native to Asia (China, India, Russia, Japan, Malaysia, etc.),[2] and it is present in North America and Europe as an introduced species and often a weed.[3][4]

Persicaria longiseta is an annual herb with stems 30 to 80 centimeters (12-32 inches) long,[5] sometimes reaching one meter(40 inches).[3] The hairless, branching stems may root at lower nodes that come in contact with the substrate. The leaves are lance-shaped and up to 8 centimeters (3.2 inches) long by 3 cm (1.2 inches) wide. They have bristly ochrea. The inflorescence is an elongate cluster up to 8 centimeters (3.2 inches) long and contains many pink flowers. The fruit is a small, smooth achene.[5]

In its native region this plant is a common weed of rice paddies. It was introduced to North America near Philadelphia around 1910 and probably spread via the railroads. It is present in much of the eastern United States and much of Canada.[6] It grows in moist habitat types such as wetlands, as well as dry and upland habitat. It can be found in meadows, marshes, mudflats, riverbanks, floodplains, levees, and lowland and upland forests. It is invasive in some areas.[3]

Tufted Knotweed is similar to other Polygonum species, particularly Polygonum persicaria (Lady's thumb). Around the stem of both these species there is a papery sheath known as an ocrea with stiff spine-like hairs at the top, but in P. caespitosum these hairs are much longer, as long as the visible portion of the ocrea, whereas in P. persicaria they are much shorter.[7][8]

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References

  1. ↑ Tropicos, Persicaria longiseta (Bruijn) Kitag.
  2. ↑ Flora of China, Polygonum longisetum Bruijn in Miquel, 1854. 长鬃蓼 chang zong liao
  3. 1 2 3 Stone, Katharine R. 2010. Persicaria longiseta. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory.
  4. ↑ Altervista Flora Italiana, Persicaria longiseta (Bruijn) Kitag.
  5. 1 2 Flora of North America. Persicaria longiseta. Flora of North America.
  6. ↑ Biota of North America Program 2014 county distribution map
  7. ↑ Mehrhoff LJ, Silander JAJ, Leicht SA, Mosher ES, Tabak NM (2003) IPANE. Invasive plant atlas of New England. Department of Ecology & Evolutionary Biology, University of Connecticut, Storrs, CT, USA.
  8. ↑ "Tufted Knotweed", Weed ID Guide, Weed Science Program, University of Missouri

External links

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