Polygonum caespitosum var. longisetum (Vascular Plants of Lost Cove Farm)

Polygonum caespitosum var. longisetum

Persicaria longiseta

Summary ⁴

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 Southeast Asia, and it is present in North America and Europe as an introduced species and often a weed.

Comments ⁵

Persicaria longiseta is morphologically similar to another Asian species, P. posumbu (Buchanan-Hamilton ex D. Don) H. Gross (= P. caespitosa). Its spread in the United States since its introduction near Philadelphia in 1910 was summarized by A. K. Paterson (2000).

Description ⁶

Botanical description: This description covers characteristics that may be relevant to fire ecology and is not meant for identification. Keys for identification are available (e.g., [13,16,34,38,57,73]).

Oriental lady's thumb is an annual [12,13,16,48,57]. Stems are prostrate or erect, and can reach 3.2 feet (1 m) in height. Leaves are alternate, thin, and lanceolate to elliptic in shape, 0.75 to 3 inches (2-7.5 cm) in length. Flowers are small, dark pink, and arranged in few to many thin spikes. Seeds are small, smooth, trigonous achenes [35].

A USDA Forest Service fact sheet reports that Oriental lady's thumb has fibrous roots and a shallow taproot [66]. Two floras report that Oriental lady's thumb may root from lower nodes [12,16]. Rhizomes and stolons are absent [12].

Fire adaptations ⁷

More info for the term: litter

As of 2010, there was no published information regarding Oriental lady's thumb adaptations to fire. The information presented here is inferred from reported botanical traits.

Oriental lady's thumb does not regenerate vegetatively (See Vegetative regeneration), so on-site plants would likely be killed by fire. Available literature suggests Oriental lady's thumb may establish after fire [15], either from the soil seed bank or dispersal from off-site sources. The requirement of moisture for Oriental lady's thumb germination suggests that its establishment would be limited in areas where fire created dry conditions (e.g., through litter consumption and soil exposure). Though many sources document Oriental lady's thumb occurring in disturbed areas, its lack of germination in disturbed forested sites without a canopy in Pennsylvania suggests that disturbance alone does not facilitate its establishment 24. This topic warrants further study.

Sources and Credits

(c) harum.koh, some rights reserved (CC BY-SA), uploaded by harum.koh, https://www.flickr.com/photos/harumkoh/15324278929/
(c) Melissa McMasters, some rights reserved (CC BY), https://www.flickr.com/photos/132545975@N04/17200822092/
(c) Toshiyuki IMAI, some rights reserved (CC BY-SA), https://www.flickr.com/photos/matsuyuki/8169119900/
Adapted by Jonathan (JC) Carpenter from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Persicaria_longiseta
(c) Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/19828598
Public Domain, http://eol.org/data_objects/24629830
Public Domain, http://eol.org/data_objects/24629841

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