Persicaria maculosa

Taxobox
name = Redshank

---

image_width = 240px
regnum = Plantae
divisio = Magnoliophyta
classis = Magnoliopsida
ordo = Caryophyllales
familia = Polygonaceae
genus = "Persicaria"
species = "P. maculosa"
binomial = "Persicaria maculosa"
binomial_authority = L.

The Redshank ("Persicaria maculosa", formerly "Polygonum persicaria") is a perennial plant from the Knotweed family Polygonaceae. It is also called Persicaria, Redleg, Lady's-thumb [ [http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=20915] ITIS, referenced 10/15/07 ] or Spotted Ladysthumb.

There are three varietes known:
*"Polygonum persicaria" var. "angustifolium" Beckh.
*"Polygonum persicaria" var. "persicaria"
*"Polygonum persicaria" var. "ruderale" (Salisb.) Meisn.

Synonyms include "P. maculata, P. persicaria, P. ruderalis, P. ruderalis, P. vulgaris, P. dubium, P. fusiforme, P. minus" and "P. puritanorum".

It grows up to 1 m high, and has narrow, lancet-shaped leaves 8-10 cm long. The leaves often have a brown or black spot. The white, pink or red flowers are in dense panicles and flower from early summer to late autumn.

It is native to Europe and Asia, where it can be mistaken for "Polygonum minus", but "P. minus" has narrower leaves, usually less than 1 cm wide, while its ear is slimmer.

It has been introduced to North America and is naturalised in all mainland states [USDA [http://plants.usda.gov/java/nameSearch?keywordquery=Persicaria+maculosa&mode=sciname&submit.x=0&submit.y=0] ] , being found along roadsides, riverbanks, and on fallow ground. In the USA, it is very similar to Pennsylvania smartweed, but Redshank has a fringe of hairs at the top of the ocrea, something which Pennsylvania smartweed lacks.

Cultivation and uses

This plant contains persicarin and tannins. In medicine, Redshank is used against diarrhoea and infections. Fresh leaves have been used to staunch bleeding.

The leaves and young shoots may be eaten as a palatable and nutritious leaf vegetable. It is often seen as a weed and rarely cultivated.

A yellow dye can be produced from this plant with alum used as a mordant.

References