Polygonum longisetum
De Bruyn
iNaturalist· cc-by-nc
(c) Sara Rall, some rights reserved (CC BY-NC)
iNaturalist· cc-by-nc
(c) katharina2525, some rights reserved (CC BY-NC)
iNaturalist· cc-by-nc
(c) katharina2525, some rights reserved (CC BY-NC)
Summary
A compact annual reaching 50 centimeters tall. Blooms May to June with seeds ripening June to August. Hermaphroditic with both male and female organs. Suitable for sandy, loamy, or clay soils with mildly acidic to mildly alkaline pH. Tolerates semi-shade or full sun and prefers consistently moist to wet soil.
Description
An annual herb. It lies along the ground or can curve upwards. It is 20-80 cm tall. The stems have many branches. The leaves have short leaf stalks and are narrowly oval and 2-8 cm long by 1-2.5 cm wide. The tip narrows to a point and the base is wedge shaped. The flowers are in groups of 4-6 in spike like groups. They can be at the ends of branches or in the axils of leaves. The flowers are white. The fruit are dry, black and 3 sided. They are 2 mm long.
Edible Uses
Young leaves can be eaten raw or cooked, though this is regarded as a famine food, used when nothing else is available. Seeds are also edible raw or cooked, though they are small and fiddly to work with.
Medicinal Uses
None known
Known Hazards
Although no specific mention has been made for this species, there have been reports that some members of this genus can cause photosensitivity in susceptible people. Many species also contain oxalic acid (the distinctive lemony flavour of sorrel) - whilst not toxic this substance can bind up other minerals making them unavailable to the body and leading to mineral deficiency. Having said that, a number of common foods such as sorrel and rhubarb contain oxalic acid and the leaves of most members of this genus are nutritious and beneficial to eat in moderate quantities. Cooking the leaves will reduce their content of oxalic acid. People with a tendency to rheumatism, arthritis, gout, kidney stones or hyperacidity should take especial caution if including this plant in their diet since it can aggravate their condition.
Distribution
In Taiwan it grows in open, grassy waste places.
Where It Grows
Asia, China, Himalayas, Japan, Korea, Japan, Malaysia, SE Asia, Taiwan,
Cultivation
We have very little information on this species and do not know if it is hardy in Britain, though judging by its native range it should succeed outdoors in most parts of the country. The following notes are based on the general needs of the genus. Succeeds in an ordinary garden soil but prefers a moisture retentive not too fertile soil in sun or part shade. Succeeds in wet soils. Repays generous treatment. Plants seem to be immune to the predations of rabbits.
Propagation
Sow seed in spring in a cold frame; germination is generally free and easy. Once seedlings are large enough to handle, prick them out into individual pots and plant out during summer if they have reached sufficient size, or overwinter in a cold frame and plant out the following spring after the last expected frosts.
Other Uses
None known Special Uses
Notes
There are about 50 Polygonum species.
Synonyms
References (4)
- Altschul, S.V.R., 1973, Drugs and Foods from Little-known Plants. Notes in Harvard University Herbaria. Harvard Univ. Press. Massachusetts. no. 849
- Flora of Taiwan Vol. 2:304
- Kuo, W. H. J., (Ed.) Taiwan's Ethnobotanical Database (1900-2000), http://tk.agron.ntu.edu.tw/ethnobot/DB1.htm
- Plants for a Future database, The Field, Penpol, Lostwithiel, Cornwall, PL22 0NG, UK. http://www.scs.leeds.ac.uk/pfaf/
