Knotweed family

 

 

 

 

 

 

 

 

 

 

 

 

 

The family name Polygonaceae is derived from Ancient Greek poly (‘many’) and gony (‘knee’ or ‘joint’), alluding to the swollen and often bent nodes on the stems of most of these plants. In numerous species, the stipules (scale-like or leaf-like appendages at the base of leaf-stalks) are fused into a stem-clasping sheath. The name is based on the genus Polygonum (below), first used in 1789 by French botanist Antoine Laurent de Jussieu (1748-1836) in his book Genera Plantarum.

The popular name knotweed alludes to several creeping species, which often form a dense tangle, a ‘knot’, whereas the name pinkweed alludes to the flower colour of many of these plants. The name smartweed refers to water pepper (Persicaria hydropiper, below), whose leaves have a peppery taste, which may ‘smart’ your mouth. Smart is an old English word, adapted from German Schmerz, which means ‘pain’.

Formerly, many members were lumped in the genus Polygonum. However, morphological and genetic research have had the effect that most of them have been transferred to various other genera, including Bistorta, Fallopia, Koenigia, Persicaria, and Reynoutria, all presented below.

Flowers of these plants only have one type of segments. Whether they are called petals or sepals is an open question. Here I call them petals.

 

 

The generic name is derived from Ancient Greek anti (‘opposite’) and gony (‘knee’, here in the meaning ‘angled’), referring to the zig-zag stems of these plants.

 

The stalked leaves are alternate, simple, narrowly heart-shaped, prominently veined, margin wavy. The inflorescences are large racemes, flowers bright pink, fragrant, with 5 petals. They turn brown with age.

The specific name is derived from Ancient Greek leptos (‘thin’) and pous (‘foot’, here in the meaning ‘stem’), thus ‘with slender stems’.

 

 

 

 

 

 

 

The generic name is derived from the Latin bis (‘twice’) and tortus (‘twisted’), referring to the twisted root of the common bistort (B. officinalis, below).

 

It is quite common on open slopes and in rocky areas, from Afghanistan eastwards through southern Tibet and northern Himalaya to Myanmar, growing at elevations between 3,000 and 4,900 m.

In Nepal, the rhizome is used for brewing tea, and also taken for stomach disorders.

The specific name is Latin, meaning ‘kindred’, presumably of another plant.

 

 

 

 

 

 

 

It has a wide range, found from Afghanistan eastwards along the Himalaya to central China, growing in shrubberies, forest edges, and open slopes.

In Nepal, the rhizome is utilized for tea, and a paste of the plant is applied to wounds.

The specific name refers to the upper leaves clasping the stem, from the Latin amplexus (‘clasped’) and‎ caulis (‘stem’).

 

 

 

 

 

 

 

 

 

It is distributed from Uttarakhand, north-western India, eastwards to Bhutan and thence northwards to central China, growing in grasslands and on open slopes at altitudes between 1,700 and 5,000 m, mainly in drier areas.

In Nepal, juice of the root is used for diarrhoea and dysentery.

The specific name is derived from Ancient Greek makros (‘long’) and phyllon (‘leaf’), presumably alluding to the leaves being rather long, compared to the width.

 

 

 

 

 

Stem to 50 cm tall, lower leaves oblong or lanceolate, parallel-sided, blade to 15 cm long and 4.5 cm wide, abruptly narrowed to a winged leaf-stalk, upper leaves sessile, sometimes clasping the stem. The inflorescence is a dense terminal head, broadly cylindrical or rounded, to 6 cm long, flowers crimson, to 4 mm long.

The specific name honours English plant collector Charles Millett (1792-1873), who corresponded with the famous British botanist William Jackson Hooker (1785-1865). Between 1827 and 1834, Millet was based in Macau, Ceylon (today Sri Lanka), the Malabar region of South India, and Java, working for the East India Company. While in Asia, he collected many plants. He returned to London in 1834.

 

 

 

 

 

This species is widespread in temperate areas of central and southern Europe, including the British Isles, eastwards to the Pacific, southwards to Morocco, Iran, and southern China. It is also a common escape in North America. In southern Europe, it is restricted to mountains. It is very common in the Alps, growing in meadows and pastures, at forest edges, and along trails, up to altitudes of about 2,100 m.

Fresh leaves are a valuable fodder, whereas they crumble if they are preserved as hay. The rhizome contains an edible starch, and the leaves were formerly used in folk medicine to treat wounds.

Popular names of this plant include snake-root, alluding to the twisted root, which resembles a moving snake. In Germany, a decoction of the root was used as a remedy for snakebites. The popular name pudding grass refers to an old usage of the leaves in northern England as an ingredient in a bitter Lent pudding, together with other herbs, oatmeal, and eggs.

 

 

 

 

 

 

 

 

 

It is found from Kashmir eastwards to Bhutan and south-eastern Tibet, growing at elevations between 3,000 and 4,500 m. It is common in wetter areas of Nepal.

In Nepal, juice of the root is utilized for fever.

The specific name is Latin, meaning ‘with leaves like Vaccinium‘ (blueberry).

 

 

 

 

 

 

 

 

 

This plant is widely distributed in subarctic and temperate areas of the Northern Hemisphere, southwards to Arizona, Spain, the Caucasus, the Himalaya, and northern Indochina.

In Nepal, the root is used for fever, seeds for cough and infections. The seeds are roasted and pickled.

Formerly, members of the Siberian chukchi people would collect the rootstock, which has a fine almond-like taste. In Nepal, the root is used for fever, seeds for cough and infections. The seeds are roasted and pickled.

The specific name is derived from the Latin vivus (‘alive’) and‎ pario (‘I bear’, i.e. offspring), alluding to the bulbils in the lower part of the spike.

 

 

 

 

 

 

 

 

 

 

 

The generic name is derived from Ancient Greek erion (‘wool’) and gony (‘knee’), alluding to the hairy nodes of the first species to be described, E. tomentosum.

 

 

 

 

 

The stems, to about 1.5 m tall, are spreading or erect, stem leaves singly or in bundles at each node, blade linear or oblanceolate, to 1.5 cm long and 5 mm wide, white-woolly or sometimes almost smooth above, greyish or green below, margin often inrolled. The inflorescence is widely branched, rounded or occasionally flat-topped, with numerous compact heads, to 2 cm across, flowers white or pinkish, to 3 mm across.

In former days, this species was widely used medicinally by various tribes for numerous ailments, including colds, headache, diarrhoea, and wounds. It was also eaten raw or used in porridges and baked items, and tea was made from leaves, stems, and root. Today, it is a very important source of honey.

The specific name is a diminutive of the Latin fascis (‘bundle’), referring to the leaf clusters.

 

 

 

 

 

It is found in south-western United States, from California eastwards to Colorado and New Mexico, and in north-western and central Mexico, growing in a variety of habitats, including sandy places, grasslands, saltbush, shrubberies, and piñon-juniper woodlands, from the lowlands to elevations around 2,000 m.

The specific name refers to the inflated stems.

 

 

 

 

 

 

 

It is a shrub, to 1 m tall, sparsely hairy or smooth, greenish, stem leaves in clusters, or sometimes singly, at the nodes, blade lanceolate or rounded, to 3 cm long and 8 mm wide, smooth and olive-green above, woolly below. The inflorescence is widely branched, with more or less dense heads to about 2.5 cm across, flowers white, pinkish, or greenish-yellow, smooth, to 3 mm across.

The specific name is Latin, meaning ‘with small leaves’.

 

 

 

 

 

The generic name is derived from the Latin fagus (‘beech’) and Ancient Greek pyros (‘wheat’), alluding to the resemblance of the nutlet to beech nuts. The common name is a corruption of the German name Buchweizen (‘beech-wheat’).

 

It occurs from Pakistan eastwards to central and southern China and northern Indochina, growing in forests, shrubberies, along trails, and in cultivated areas. In the Himalaya, it may be observed up to elevations around 3,400 m.

In Nepal, tender parts are cooked as a vegetable, the leaves cut for fodder, and the seeds used for stomach disorders.

The specific name is Latin, meaning ‘with many shoots’.

 

 

 

 

 

Stem erect or ascending, green or reddish, branched, sometimes growing to about 1 m tall. The leaves are stalked, blade triangular, heart-shaped, or spear-shaped, prominently veined, to 8 cm long and wide, margin hairy, tip pointed. Inflorescences are terminal or axillary, panicle-like clusters, with white or pale pink flowers, petals elliptic or obovate, to 5 mm long. The nutlets are sharply angled, to about 7 mm long.

The specific name is Latin, meaning ‘edible’, derived from esca (‘food’) and ulentus (‘abounding in’).

 

 

 

 

 

 

 

 

 

 

 

The generic name probably honours Italian botanist and anatomist Gabriele Falloppio (1523-1562), who was superintendent of the botanical garden at Padua.

 

Black bindweed mostly grows on disturbed or cultivated land, and it may sometimes be a noxious weed. It is widely distributed in temperate areas of Eurasia, southwards to northern Africa, the Himalaya, and northern Indochina. In the northern parts of its range it is found down to sea level, whereas in the southern parts it is restricted to mountains. In China, it has been observed up to an elevation of 3,600 m. It has become naturalized in many other areas of the world.

The seeds are edible. Remains have been found in Bronze Age middens, indicating that it was a food crop in those days.

The specific name refers to its climbing habit and the shape of the leaves, by which it resembles bindweeds, genus Convolvulus, described on the page Plants: Morning glories and bindweeds.

 

 

 

 

 

 

 

 

 

In Nepal, the slightly acid stems of some members are chewed when young.

The generic name commemorates Baltic-German botanist and physician Johann Gerhard König (1728-1785), a pupil of Swedish naturalist Carl Linnaeus (1707-78) in 1757. While living in Denmark 1759-67, he was sent to Iceland to examine the flora. Later, he served in the Danish Tranquebar Mission in South India, before serving under the Nawab of Arcot, and later the English East India Company. He collected many plants from the region.

 

It is widely distributed, from southern and eastern Europe eastwards across the Middle East and Central Asia to the Pacific Ocean, southwards to Iran, the Himalaya, and northern Indochina, growing in shrubberies, on open slopes, and along streams.

The stem is edible when cooked.

 

 

 

 

 

 

 

It is found from Uttarakhand, north-western India, eastwards to northern Myanmar and south-western China, growing in open forests and shrubberies, and along streams.

In Nepal, tender parts are cooked as a vegetable.

The specific name was given in allusion to the bell-shaped flowers, from the Latin campanula (’little bell’).

 

 

 

 

 

This plant is widespread in subarctic regions, extending into temperate areas southwards to Arizona, the British Isles, Pakistan, Ladakh, and western China. It grows in humid grasslands and along streams.

The specific name refers to Iceland, where König (see generic name above) first collected this species in 1765.

 

 

 

 

 

It is distributed from Uttarakhand, north-western India, eastwards to southern China, and thence southwards through Indochina to Indonesia.

In Nepal, tender parts are cooked as a vegetable, and also pickled.

The specific name is Latin, meaning ‘soft’ or ‘delicate’, alluding to the downy-hairy stems and leaves.

 

 

 

 

 

 

 

It grows in forests and open areas, and at streamsides, from Afghanistan eastwards to northern Myanmar and south-western China, found at elevations between 2,000 and 4,500 m.

In Nepal, tender parts are cooked as a vegetable.

This species was previously known as Persicaria polystachya, Persicaria wallichii, or Polygonum wallichii.

The specific name is derived from Ancient Greek polys (‘many’) and stachys, which originally meant ‘an ear of grain’, but in a botanical context used for ‘spike’ (an inflorescence with many stalkless seeds along a central axis). Thus, polystachya means ‘with many spikes’, alluding to the abundant number of (false) spikes on this plant.

 

 

 

 

 

 

 

 

 

This species is distributed in dry and stony regions, from Afghanistan eastwards across northern Pakistan, Ladakh, and Tibet to northern Nepal and northern Arunachal Pradesh, found at elevations between 3,300 and 5,600 m.

It is used medicinally for dysentery.

The specific name is derived from the Latin tortus (‘twisted’) and osus (‘plenty’), referring to the twisted leaves.

 

 

 

 

 

 

 

 

 

The generic name is derived from Ancient Greek oxys (‘sour’) and aria (‘possessing’), alluding to the acidic leaves of these plants.

 

The native range of this species is subarctic and temperate regions of the Northern Hemisphere, southwards to Arizona, Iran, the Himalaya, and western China, growing on open slopes and grazing grounds, and along streams and trails. In Central Asia, it may be encountered up to altitudes around 5,200 m.

The leaves are edible, raw or cooked. In Nepal, root, stem, and leaves are used for treatment of dysentery.

The specific name is derived from Ancient Greek dis (‘two’) and gyne (‘woman’), referring to the flower having 2 stigmas.

 

 

 

 

 

 

 

 

 

 

 

 

 

The generic name is derived from the Latin persica (‘peach-like’), alluding to the leaves of some members resembling peach leaves.

 

It is native to subarctic and temperate areas of the Northern Henisphere, southwards to Central America, Arabia, and China, and also occurs in Ethiopia, Kenya, and South Africa.

The specific name is derived from the Greek amfi (‘both sides’) and bios (‘life’), thus ‘living on both sides’, referring to the fact that the plant is found in water as well as on dry land.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

It is distributed from Pakistan eastwards to Taiwan, southwards to Sri Lanka and northern Malaysia, growing in a variety of habitats, including rocks, stone fences, and open slopes, and along trails, found at elevations between 600 and 3,500 m.

In Nepal, a paste of the plant is applied to boils and wounds, and its juice is taken for stomach problems. The plant is collected for fodder.

The specific name is Latin, meaning ‘forming a head’, alluding to the globular inflorescence.

 

 

 

 

 

 

 

 

 

This species grows in forests, shrubberies, and on open slopes, from sea level to an altitude of about 3,000 m. It is distributed from Pakistan eastwards to Korea and Japan, southwards to Sri Lanka, Indonesia, and the Philippines.

 

 

 

 

 

 

 

 

 

 

 

It is partial to wet areas, growing along streams and in marshes. It is very widely distributed in warmer regions, in south-eastern United States, Mexico, Central America, and in large parts of South America, in Sudan and Ethiopia, and the Arabian Peninsula, and from Pakistan eastwards to Taiwan, southwards to Sri Lanka, Indochina, and the Philippines.

 

 

 

 

 

Very widely distributed, found from the entire Europe eastwards across Central Asia to the Pacific Ocean, southwards to North Africa, Iran, Sri Lanka, Indonesia, and Australia. It grows in wet meadows, and along rivers and ponds.

In Nepal, the plant is boiled, and the filtered water is taken to expel intestinal parasites. The plant is also strewn in water to stupefy fish.

The specific name is derived from Ancient Greek hydor (‘water’) and peperi (‘pepper’), ultimately from Sanskrit pippali. It refers to the leaves, which have a strong peppery taste, also reflected in the name smartweed, derived from old English smeortan (‘to cause pain’), originally from German Schmerz (‘pain’).

In his delightful book All about Weeds, American botanist Edwin Spencer (1881-1964) writes: “There are a great many species (…) which look somewhat like this weed, but most of them lack the ‘smart’ taste entirely, and none of them possess the fire of hydropiper.”

 

 

 

 

 

 

 

It is an annual, stem to about 90 cm tall, green or reddish, smooth or downy-haired, swollen at the nodes. Leaves almost sessile, lanceolate or narrowly elliptic, to 15 cm long and 3 cm wide, the upperside often with a dark blotch in the centre, margin hairy. The sheath is brownish or transparent, to 3 cm long, sometimes fringed with a few hairs above. The inflorescences are terminal or axillary, dense spikes, erect or nodding, to 8 cm long, often with several spikes close together, forming what looks like a loose panicle. Corolla pink or white, petals to 3 mm long.

The young leaves are edible raw, and in some areas young plants are cooked as a vegetable. Medicinally, it is used as an astringent, and for inflammation, stomach problems, and fever. The plant produces a soft, white, soap-like mass, used for bathing and washing clothes.

The specific name is derived from the Latin lapathi, an old name for docks and sorrels (Rumex, see below), and folius (‘leaf’). The name smartweed alludes to its similarity to the ‘true’ smartweed, P. hydropiper (above).

This species is very similar to the following one, and telling them apart is far from easy. A detailed identification key is found in this article: M. Wilcox, 2021. Recording Persicaria maculosa and P. lapathifolia (Polygonaceae). British & Irish Botany 3(3): 349-361, web version Wilcox+Final.pdf.

 

 

 

 

 

 

 

 

 

It is native to temperate and subtropical regions of Eurasia and northern Africa, but has become naturalized in numerous countries across the globe.

The specific name is Latin, meaning ‘spotted’, referring to numerous glands on the underside of the leaves – which, however, are often insignificant and hard to see.

 

 

 

 

 

It grows in many habitats, including streamsides, roadsides, and wastelands. As its specific name implies, it is an eastern species, occurring naturally from the Indian Subcontinent eastwards to Taiwan, and thence northwards to Ussuriland (south-eastern Siberia), southwards to the Philippines, Indonesia, New Guinea, and eastern Australia. However, it is widely cultivated and has become naturalized in numerous countries around the world.

Medicinally, it has a wide range of uses, including treating rheumatism, promoting digestion, aiding diuresis, and activating blood circulation. It is also used against inflammation and diarrhoea.

 

 

 

 

 

This plant grows in shrubberies and open areas, and along trails and roads. It is very widely distributed, from Turkey and the Caucasus eastwards to Ussuriland (south-eastern Siberia), China, Korea, Japan, Taiwan, the Indian Subcontinent, Indochina, Indonesia, New Guinea, and the Philippines. It has also been accidentally introduced elsewhere and has become naturalized in many places. In North America and Europe, it is regarded as an invasive species.

Ripe fruits are edible. In Nepal, tender parts are cooked as a vegetable, and juice of the leaves is taken for backache. It is also used for various purposes in traditional Chinese medicine. The foliage provides good fodder, and stems can be used to make ropes.

The specific name is a botanical term, used when the stem seemingly passes through the leaf blade, from the Latin per (‘through’) and foliatus (‘leafy’), in this case alluding to the leaf-like ears at the nodes. Common names include mile-a-minute vine, which alludes to the rapid growth of the plant, and devil’s tail and climbing tearthumb, which both refer to its vicious prickles.

 

 

 

 

 

It is distributed from the Indian Subcontinent eastwards to China, Korea, Japan, and Taiwan, and thence southwards to Indonesia, growing in shrubberies and open areas, and along fields and streams.

In Nepal, it is strewn in streams to stupefy fish.

The specific name is Latin, meaning ‘downy-hairy’ – not a descriptive name!

This species resembles Persicaria hydropiper (above), but may be identified by the stem and the inflorescence, which are both often red.

 

 

 

 

 

It is found in grasslands, shrubberies, and open humid slopes, from Uttarakhand, north-western India, eastwards to eastern China and Taiwan, and thence southwards to Java and the Philippines.

In Nepal, young parts are cooked as a vegetable.

The botanical meaning of the specific name is ‘pointing backwards from the tip’, alluding to the lobes on the leaves.

 

 

 

 

 

This plant grows in forests and shrubberies, and on open slopes, found up to elevations around 1,500 m. It is distributed from Ussuriland (south-eastern Siberia), southwards through eastern China, Korea, Japan, and Taiwan to northern Vietnam.

Young parts may be cooked as a vegetable.

The specific name is derived from the Latin sentis (‘thorn’) and osus (‘full of’) – a descriptive name!

 

 

 

 

 

The generic name is explained at the top of this page. The common names allude to the fact that these plants often form a dense tangle, a ‘knot’.

 

The specific name is derived from the Latin arena (‘sand’), thus ‘of the sand’, i.e. ‘growing in sand’.

 

 

 

 

 

Prostrate knotweed is very variable, and in its widest sense it contains a number of species or subspecies, including arenastrum (above). It is branched from the base, stems mostly creeping, but occasionally ascending, growing to 70 cm long/tall, sometimes more. Leaves are numerous, short-stalked, linear, lanceolate, or elliptic, on the main stem to 4 cm long and 1.2 cm wide, smaller on the branches, margin entire, tip pointed or rounded. The small flowers, to 4 mm across, are solitary or in small clusters at the nodes, corolla white or pinkish, often with a greenish base.

This species is eagerly eaten by cows and chickens, and the seeds are much relished by small birds. This was observed by Swedish naturalist Carl Linnaeus (1707-78), when he named the plant aviculare, derived from the Latin avicula (‘small bird’).

In folk medicine, the juice has been used to stop nose-bleed and other types of bleeding. Tea made from the plant was used for diarrhoea, cough, bronchitis, and bleeding haemorrhoids.

In his play A Midsummer Night’s Dream, William Shakespeare (1564-1616) calls this plant “the hindering knotgrass”. In those days, it was believed that its juice would interfere with the growth of young children and domestic animals.

 

 

 

 

 

 

 

This species is found in South and East Asia, Indochina, the Philippines, Australia, most of Africa, and Madagascar, growing in dry rice fields and humid grasslands, and along trails.

In Nepal, the plant is boiled, and the juice taken for dysentery, juice of the root for stomach trouble. Tender parts are cooked as a vegetable.

 

 

 

 

 

The generic name commemorates Charles de Saint Omer (1533-1569), Lord of Reynoutre. Flemish botanist Matthias van Lobel (1538-1616) testifies “dat dezelve aan de Kruidkunde zeer veel dienst gedaan heest.” (‘that the same to Herbology has done much service’).

 

This large plant may grow to 4 m tall, but under harsh conditions it is often much smaller (see upper photo below). It has hollow stems with distinct nodes, making it resemble bamboo. The leaves are broadly ovate, to 14 cm long and 9 cm wide, base mostly truncate, but varies a great deal, margin entire. The small flowers, white or cream-coloured, are arranged in racemes, to 15 cm long. The spathulate, notched fruits are white, cream-coloured, or pink.

Japanese knotweed was introduced to Europe and North America in the 1800s and soon became a popular garden plant because of its bamboo-like appearance, vigorous growth, and pretty inflorescences. However, it quickly turned into a menace, as it spread beyond control, its strong root system being able to “damage concrete foundations, buildings, flood defences, roads, paving, retaining walls, and architectural sites.” (Source: gardenroots.co.uk)

Japanese knotweed is listed by the World Conservation Union as one of the world’s worst invasive species.

 

 

 

 

 

 

 

 

 

It is very similar to F. japonica, but has larger leaves, to 40 cm long and 28 cm broad, with almost heart-shaped base and a wavy margin. The shoots are tender and edible.

 

 

 

 

 

The basal leaves are large, ovate or heart-shaped, the small green flowers are in spike-like panicles, and the fruit is a nut, broadly 3-winged, often red or purple.

The generic name is a Latinized form of Ancient Greek rheon, the classical name of rhubarb, ultimately from the Persian name of these plants, rewand.

 

This plant is distributed from Uttarakhand, north-western India, eastwards along the Himalaya to northern Myanmar and western China, growing on open slopes and in shrubberies, at elevations between 2,800 and 4,300 m.

The roots are used medicinally. In Nepal, the leaf stalks are pickled.

The specific name is Latin, meaning ‘pointed’, referring to the leaf shape.

 

 

 

 

 

It is found from Pakistan eastwards to Myanmar and south-eastern Tibet, growing on open slopes and in grassy areas, at elevations between 3,000 and 4,300 m.

In Nepal, the leaf-stalks are dried and pickled. The rhizome is used as a purgative, astringent, and stomachic, and it also yields a yellow dye. The species is threatened by excessive collecting.

The specific name is Latin, meaning ‘southern’, probably alluding to this species being one of the most southerly of the genus.

 

 

 

 

 

 

 

It grows in rocky areas at altitudes between 3,600 and 4,800 m, from eastern Nepal eastwards to south-eastern Tibet.

Leaf-stalks can be eaten, raw or pickled. The leaves are used as a substitute for tobacco. The plant is threatened due to excessive collecting.

 

 

 

 

 

It grows in dry areas at elevations between 2,500 and 4,600 m, from Afghanistan eastwards through northern Pakistan, Ladakh, and northern Himachal Pradesh to Tibet.

 

 

 

 

 

It is distributed in dry areas, from Pakistan eastwards to south-western Tibet and western Nepal, growing at elevations between 2,000 and 4,500 m.

The stalk is edible. The root is used for stomach and intestinal disorders, root, stem, and leaves as a purgative, and juice of the plant is applied to boils and wounds. A dye is obtained from the root.

The specific name was given in honour of English botanist Philip Barker Webb (1793-1854), who collected plants in Italy, Spain, Portugal, Morocco, the Canary Islands, and Brazil.

 

 

 

 

 

 

 

 

 

 

The fruit is mostly a triangular nutlet, often winged, arranged in dense clusters, often conspicuously reddish-brown when ripe.

An old home remedy, if you are stung by a nettle, is to apply the juice of dock to the affected area, which will afford instant relief. An old rhyme says:

 

 

 

It is native to the major part of Eurasia, from Iceland eastwards to central Siberia and Japan, southwards to Morocco, Pakistan, and southern China, growing in grasslands and other open habitats. It is sometimes cultivated as a leaf vegetable.

The specific name is derived from the Latin acetum (‘vinegar’) and osus (‘full of’), thus ‘sour’, alluding to the acidic leaves of this plant.

 

 

 

 

 

 

 

 

 

It is native to subarctic and temperate areas of Eurasia, found in a vast area, from Greenland eastwards to the Pacific Ocean, southwards to northern Africa, Iran, and southern China, growing in disturbed places, such as roadsides, cultivated fields, waste places, lawns, meadows, and along railroads, usually in acidic soils.

The specific name is constructed of acetosa, the specific name of the common sorrel, and ella, a suffix denoting something diminutive, indicating that it is similar to common sorrel, but smaller.

The common name was first used in England around 1800. It may allude to the plant growing in acidic soils, where sheep often graze. In Spanish, this species is called sangre de toro (‘bull’s blood’), undoubtedly stemming from bull fights, which were formerly common in Spain. At a distance, a large growth can resemble a pool of blood.

 

 

 

 

 

 

 

 

 

 

 

Shortly after the snow has melted, the yellowish-green to copper-red young leaves grow from the rhizomes. They become very large and long-stalked, blade heart-shaped or ovate, smooth, to 50 cm long, with wavy margin, stem leaves smaller, alternate, oblong or lanceolate. The stipules form a sheath around the stem.

The inflorescences are much-branched, dense, terminal compound panicles with hundreds of tiny greenish flowers. The fruit is a reddish-brown, triangular, winged nutlet, which may remain viable for more than 10 years.

This species is native to mountains of central and southern Europe, as well as Ukraine and Turkey, eastwards to the Caucasus and north-western Iran. It grows in all kinds of open areas on nutritious soils, up to an elevation of about 2,600 m.

A popular name of this plant is monk’s rhubarb, alluding to the leaves, which are edible, raw or cooked. They make an excellent spinach.

 

 

 

 

 

 

 

 

 

 

 

This plant grows in stagnant freshwater, found from Afghanistan and northern Pakistan eastwards through Ladakh to western Tibet, growing at elevations between 3,000 and 4,200 m.

The specific name is Latin, meaning ‘angular’, alluding to the zigzag flower stems.

 

 

 

 

 

This species is distributed in the major part of Europe, eastwards to Kazakhstan, southwards to northern Africa, Arabia, and western Himalaya. An isolated population in southern Africa has possibly been established from escapes, as it has been introduced to many other places around the globe. It grows in humid areas, including marshes, meadows, lake shores, ditches, and coastal wet places, found up to elevations around 1,500 m.

The specific name is derived from the Latin conglomerare (‘to pile into a heap’), thus ‘clustered’.

 

 

 

 

 

Stem erect, branched, usually below 1 m tall, occasionally to 1.5 m, leaves lanceolate or sometimes almost linear, to 30 cm long and 6 cm wide, base truncate or somewhat heart-shaped, margins entire, strongly wavy, tip pointed. Inflorescences are dense terminal panicles, flowers 10-25 in whorls, petals ovate, to 6 mm long and 5 mm broad, nuts reddish-brown, to 3 mm long and 2 mm wide.

The specific name is Latin, meaning ‘curly’, alluding to the strongly wavy leaf margin.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This plant is distributed from Afghanistan across southern Tibet and the Himalaya to northern Myanmar and central China, growing in cultivated areas and stone fences, on rocks, and along streams, at elevations between 1,000 and 3,200 m.

In Nepal, juice of the plant is taken for dysentery, and the root is chewed for sore throat. Tender parts are pickled. Dried leaves are collected for fodder,

The specific name is Latin, meaning ‘spear-shaped’, referring to the leaf shape.

 

 

 

 

 

It grows in wet areas, such as lake sides, along streams, and in wet meadows, often standing in water. It is distributed in most of Europe, eastwards to south-western Siberia and the Caucasus, southwards to Spain and Turkey.

The specific name is derived from Ancient Greek hydor (‘water’), and the Latin lapathi, an old name for docks and sorrels.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

It is distributed in south-western North America, from California eastwards to Oklahoma and Texas, and thence northwards to Montana, southwards to the Mexican states Baja California and Chihuahua, growing in sandy and rocky places on alkaline soils, occasionally up to elevations around 2,000 m.

The specific name is derived from Ancient Greek hymen (‘membrane’) and the Latin sepalum (‘sepal’), alluding to the inner 3 of the 6 flower segments forming papery wings, which surround the fruit.

The common name canaigre probably stems from Mexican Spanish caña agria (‘sour cane’), referring to the acidic, but edible stems.

 

 

 

 

 

Stem erect, furrowed, to about 1 m tall, basal leaves short-stalked, to 25 cm long and 10 cm wide, with wavy margin. Inflorescences are terminal panicles with flowers in multiple whorls, petals pale green, with irregularly toothed margin, nutlet to 2.5 mm long, broadly ovoid with 3 sharp edges, dark brown.

The leaves are cooked as a vegetable or added to soup, and they may be dried for later use. The nutlets are also edible, used with rice or ground into a powder for making dumplings.

Despite being slightly toxic, this plant is utilized in traditional Chinese medicine, the root as a detoxifier and a laxative, root and fruit to stop bleeding and relieve constipation. All parts can be used to kill insects.

 

 

 

 

 

 

 

The stem is erect, branched on the upper half, to 1.5 m tall, leaves very large, to 50 cm long and 15 cm wide, broadly lanceolate, tapering at both ends, base sometimes slightly heart-shaped, margin entire, wavy. Inflorescences are dense terminal panicles on the upper half of the stem, flowers 10-20 together in whorls, petals rounded or kidney-shaped, to 7 mm across, nutlets dark brown, to 3.5 mm long and 2 mm broad.

The specific name is Latin, meaning ‘with long leaves’.

 

 

 

 

 

 

 

It is a shrub, to 2.5 m tall, many-branched, with dense foliage. Leaves are broadly ovate, with a rounded tip, fleshy and pale green. Inflorescences are in terminal panicles, with tiny greenish flowers, and the fruits are reddish.

Research indicates that this species contains antidiabetic properties. (Source: pubmed.ncbi.nlm.nih.gov/30744418)

The specific name is derived from the Latin luna (‘moon’), thus ‘moon-shaped’, presumably referring to the leaves.

 

 

 

 

 

Despite its specific name, which in the Latin means ‘growing at sea shores’, this plant may be encountered in freshwater habitats, and also in drier areas, such as waste places.

The stem may be erect, to about 80 cm tall, but the plant is often prostrate. The leaves are lanceolate or linear, rarely oblong, usually gradually tapering at both ends, to about 30 cm long and 5 cm wide, but often much smaller, base wedge-shaped, margin entire, sometimes wavy. Inflorescences are terminal dense panicles on the upper half of the stem, golden or greenish-yellow, flowers 15-30 together in dense whorls, petals narrowly triangular, to 3 mm long and 1.5 mm broad, strongly toothed, bristly. Nutlets are pale brown, to 2 mm long and 1 mm wide.

 

 

 

 

 

 

 

 

 

 

 

It grows in grasslands, ditches, and open areas, and along trails, distributed from Italy and the Balkans eastwards across the Middle East and southern Central Asia to Japan, southwards to eastern and southern Africa, Madagascar, Sri Lanka, and Java. In Central Asia, it may be encountered up to elevations around 4,300 m.

In Nepal, tender parts are cooked as a vegetable, and also fermented to make gundruk (fermented leaves, see Arisaema utile on the page Plants: Himalayan flora 1). Root and leaves are used for various ailments, including eye trouble, cough, colds, headache, boils, swelling of gums, and also to expel intestinal worms.

R. dentatus is quite similar, but there are only 4-5 straight teeth along the margin of the fruit. It has a similar distribution.

 

 

 

 

 

 

 

 

 

Stem erect, branched, to 1.5 m tall, leaves oblong or ovate, to 40 cm long and 15 cm wide, base usually heart-shaped, occasionally rounded, rarely square-cut, margin entire, flat or wavy, tip blunt. Inflorescences are terminal panicles, flowers 10-25 together in lax whorls, petals triangular, to 6 mm long and 3.5 mm wide, margin usually with 2-5 straight teeth on both sides, to 1.8 mm long. Nutlets are reddish-brown, to 2.7 mm long and 1,7 mm broad.

The specific name is derived from the Latin obtusus (‘blunt’) and folium (‘leaf’).

 

 

 

 

 

 

 

 

 

 

 

 

 

It occurs from the Czech Republic and Italy eastwards through the Middle East and Central Asia to northern China and Korea, southwards to Iran, the Himalaya, and northern Indochina. It grows in fallow fields and ditches, and along trails, at elevations between 2,100 and 4,100 m.

 

 

 

 

 

 

 

The stem is erect, branched, to 90 cm tall, leaves oblong or lanceolate, to 30 cm long and 6 cm wide, base rounded, square-cut, or somewhat heart-shaped, margin entire, flat or slightly wavy, tip pointed. Inflorescences are lax, interrupted, terminal panicles on the upper two thirds of the stem, usually leafless, flowers 10-20 together in lax whorls, which are far apart, petals oblong or lanceolate, to 3 mm long and 1.5 mm broad. Nutlets dark reddish-brown or almost black, to 1.5 mm long and wide.

It has two distinct forms, by some authorities regarded as varieties: var. sanguineus (red-veined dock), which has distinct red leaf veins, and var. viridis, which lacks these red veins, or they are indistinct. The specific name is Latin, meaning ‘blood-coloured’. It probably refers to the plant attaining a bright reddish-brown colour when withering, or, in case of var. sanguineus, it may allude to the red leaf veins. The variety name viridis is Latin, meaning ‘green’, alluding to the leaves, which do not have red veins.

The pictures below all show the variety viridis.

 

 

 

 

 

 

 

 

 

 

 

This plant is indigenous in a vast area, from western Europe eastwards to the Pacific Ocean, and from Scandinavia and Siberia southwards to the Mediterranean, the Caucasus, Xinjiang, and northern China. It grows in a wide variety of open habitats, including fallow fields, roadsides, waste places, grassy areas, and forest edges.

The specific name is Latin, meaning ‘with a thyrse inflorescence’, i.e. having a compact panicle with an obscure main axis and cymose subaxes. Cymose means that the main and branch stems each end in a flower that opens before those below it or to its side.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This shrub, sometimes scrambling over other plants, may grow to 3 m tall, stem smooth, furrowed, leaves elliptic, to 9 cm long and 3 cm wide, tip pointed base spear-shaped, basal lobes to 5 mm long and 2 mm wide, reflexed. Flowers 2-6 together in whorls, outer petals brownish, to 2 mm long, inner petals red or reddish-brown, circular, to 7 mm across. Nut ovoid, to 2.5 mm long and 1 mm broad, brown, shining.

Young leaves and stems are edible, eaten raw. A decoction of the leaves is used to treat coughs, rheumatism, and stomach trouble. Formerly, a decoction of the root was utilized to treat smallpox.