''Ranunculus'' is a large genus of about almost 1700 to more than 1800

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

s in the family

Ranunculaceae Ranunculaceae (buttercup or crowfoot family; Latin "little frog", from "frog") is a family of over 2,000 known species of flowering plants in 43 genera, distributed worldwide. The largest genera are ''Ranunculus'' (600 species), ''Delphinium' ...

. Members of the genus are known as buttercups, spearworts and water crowfoots. The genus is distributed in Europe, North America and South America. The familiar and widespread buttercup of gardens throughout Northern Europe (and introduced elsewhere) is the creeping buttercup ''

Ranunculus repens ''Ranunculus repens'', the creeping buttercup, is a flowering plant in the buttercup family Ranunculaceae, native to Europe, Asia and northwestern Africa. Habitat It is a very common weed of agricultural land and gardens, spreading quickly by it ...

'', which has extremely tough and tenacious roots. Two other species are also widespread, the bulbous buttercup ''

Ranunculus bulbosus ''Ranunculus bulbosus'', commonly known as bulbous buttercup or St. Anthony's turnip, is a perennial flowering plant in the buttercup family Ranunculaceae. It has bright yellow flowers, and deeply divided, three-lobed long-petioled basal leaves. ...

'' and the much taller meadow buttercup ''

Ranunculus acris ''Ranunculus acris'' is a species of flowering plant in the family Ranunculaceae, and is one of the more common buttercups across Europe and temperate Eurasia. Common names include meadow buttercup, tall buttercup, common buttercup and giant but ...

''. In ornamental gardens, all three are often regarded as

weed A weed is a plant considered undesirable in a particular situation, "a plant in the wrong place", or a plant growing where it is not wanted.Harlan, J. R., & deWet, J. M. (1965). Some thoughts about weeds. ''Economic botany'', ''19''(1), 16-24. ...

s. Buttercups usually flower in the spring, but flowers may be found throughout the summer, especially where the plants are growing as opportunistic colonizers, as in the case of garden weeds. The water crowfoots (''Ranunculus'' subgenus ''Batrachium''), which grow in still or running water, are sometimes treated in a separate genus ''Batrachium'' (from

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

, "frog"). They have two different leaf types, thread-like leaves underwater and broader floating leaves. In some species, such as '' R. aquatilis'', a third, intermediate leaf type occurs. ''Ranunculus'' species are used as food by the

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. ...

e of some

Lepidoptera Lepidoptera ( ) is an order (biology), order of insects that includes butterfly, butterflies and moths (both are called lepidopterans). About 180,000 species of the Lepidoptera are described, in 126 Family (biology), families and 46 Taxonomic r ...

species including the

Hebrew character The Hebrew character (''Orthosia gothica'') is a moth in the family Noctuidae. The species was first described by Carl Linnaeus in his 1758 10th edition of ''Systema Naturae''. It is found throughout Europe. Both the common and binomial names ...

and

small angle shades The small angle shades (''Euplexia lucipara'') is a moth of the family Noctuidae. It is distributed throughout the Palearctic. The species was first described by Carl Linnaeus in his 1758 10th edition of ''Systema Naturae''. As the common name ...

. Some species are popular ornamental flowers in

horticulture Horticulture is the branch of agriculture that deals with the art, science, technology, and business of plant cultivation. It includes the cultivation of fruits, vegetables, nuts, seeds, herbs, sprouts, mushrooms, algae, flowers, seaweeds and no ...

, with many

cultivar A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture ...

s selected for large and brightly coloured flowers.

Description

Plant

Buttercups are mostly

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wid ...

, but occasionally annual or

biennial Biennial means (an event) lasting for two years or occurring every two years. The related term biennium is used in reference to a period of two years. In particular, it can refer to: * Biennial plant, a plant which blooms in its second year and th ...

herbaceous Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition of t ...

, aquatic or terrestrial plants, often with leaves in a rosette at the base of the stem. In many perennial species runners are sent out that will develop new plants with roots and rosettes at the distanced nodes. The leaves lack

stipule In botany, a stipule is an outgrowth typically borne on both sides (sometimes on just one side) of the base of a leafstalk (the petiole). Stipules are considered part of the anatomy of the leaf of a typical flowering plant, although in many speci ...

s, have petioles, are

palmately veined A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, st ...

, entire, more or less deeply incised, or compound, and leaflets or leaf segments may be very fine and linear in aquatic species.

Flowers

The

hermaphrodite flower Plant reproductive morphology is the study of the physical form and structure (the morphology) of those parts of plants directly or indirectly concerned with sexual reproduction. Among all living organisms, flowers, which are the reproductive s ...

s are single or in a cyme, have usually five (but occasionally as few as three or as many as seven)

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coine ...

s and usually, five yellow, greenish or white petals that are sometimes flushed with red, purple or pink (but the petals may be absent or have a different, sometimes much higher number). At the base of each petal is usually one nectary gland that is naked or may be covered by a scale. Anthers may be few, but often many are arranged in a spiral, are yellow or sometimes white, and with yellow

pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophyt ...

. The sometimes few but mostly many green or yellow

carpel Gynoecium (; ) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) ''pistils'' ...

s are not fused and are also arranged in a spiral, mostly on a globe or dome-shaped receptacle.

Reflective petals

The petals of buttercups are often highly

lustrous Lustre (British English) or luster (American English; see spelling differences) is the way light interacts with the surface of a crystal, rock, or mineral. The word traces its origins back to the Latin ''lux'', meaning "light", and generally ...

, especially in yellow species, owing to a special coloration mechanism: the petal's upper surface is very smooth causing a mirror-like reflection. The flash aids in attracting

pollinating Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, birds, a ...

insects and

temperature regulation Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature ...

of the flower's reproductive organs. File:Ranunculus glacialis.jpg, Glacier buttercup '' Ranunculus glacialis'' File:Ranunculus glaberrimus 1763f.JPG, Sagebrush buttercup ('' Ranunculus glaberrimus'') File:Ranunculus macro.jpg, Creeping buttercup (''

'') File:Heart of gold.JPG, '' Ranunculus asiaticus'', a cultivated form

Fruit

The fruits (in this case called

achene An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and indehiscent (they do not ope ...

s) may be smooth or hairy, winged, nobby or have hooked spines.

Naming

The genus name ''Ranunculus'' is

Late Latin Late Latin ( la, Latinitas serior) is the scholarly name for the form of Literary Latin of late antiquity.Roberts (1996), p. 537. English dictionary definitions of Late Latin date this period from the , and continuing into the 7th century in t ...

for "little frog", the diminutive of ''rana''. This probably refers to many species being found near water, like frogs. The common name ''buttercup'' may derive from a false belief that the plants give

butter Butter is a dairy product made from the fat and protein components of churned cream. It is a semi-solid emulsion at room temperature, consisting of approximately 80% butterfat. It is used at room temperature as a spread, melted as a condimen ...

its characteristic yellow hue (in fact it is poisonous to cows and other livestock). A popular children's game involves holding a buttercup up to the chin; a yellow reflection is supposed to indicate a fondness for butter. In ancient Rome, a species of buttercup was held to the skin by slaves attempting to remove forehead tattoos made by their owners. In the interior of the Pacific Northwest of the United States, the buttercup is called "Coyote's eyes"— in

Nez Perce The Nez Percé (; autonym in Nez Perce language: , meaning "we, the people") are an Indigenous people of the Plateau who are presumed to have lived on the Columbia River Plateau in the Pacific Northwest region for at least 11,500 years.Ames, K ...

and in

Sahaptin The Sahaptin are a number of Native American tribes who speak dialects of the Sahaptin language. The Sahaptin tribes inhabited territory along the Columbia River and its tributaries in the Pacific Northwest region of the United States. Sahaptin-s ...

. In the legend,

Coyote The coyote (''Canis latrans'') is a species of canis, canine native to North America. It is smaller than its close relative, the wolf, and slightly smaller than the closely related eastern wolf and red wolf. It fills much of the same ecologica ...

was tossing his eyes up in the air and catching them again when Eagle snatched them. Unable to see, Coyote made eyes from the buttercup.

Splitting of the genus

Molecular investigation of the genus has revealed that ''Ranunculus'' is not monophyletic with respect to a number of other recognized genera in the family—e.g. ''Ceratocephala'', ''Halerpestes'', '' Hamadryas'', ''

Laccopetalum ''Laccopetalum'' is a monotypic genus of flowering plants in the family Ranunculaceae. The genus contains only one species, ''Laccopetalum giganteum'', which is endemic to Peru , image_flag = Flag of Peru.svg , image_coat ...

'', ''

Myosurus The genus ''Myosurus'', or mousetail, belongs to the buttercup family (Ranunculaceae). It comprises about 15 species of annual scapose herbs. These herbs are nearly cosmopolitan (lacking in eastern Asia and tropical regions), with a center of d ...

'', '' Oxygraphis'', '' Paroxygraphis'' and '' Trautvetteria''. A proposal to split ''Ranunculus'' into several genera has thus been published in a new classification for the tribe Ranunculeae. The split (and often re-recognized) genera include ''Arcteranthis'' Greene, '' Beckwithia'' Jeps., ''Callianthemoides'' Tamura, '' Coptidium'' (Prantl) Beurl. ex Rydb., ''Cyrtorhyncha'' Nutt. ex Torr. & A.Gray, '' Ficaria'' Guett., '' Krapfia'' DC., '' Kumlienia'' E. Greene and ''Peltocalathos'' Tamura. Not all taxonomists and users accept this splitting of the genus, and it can alternatively be treated in the broad sense.

Pharmacological activity

The most common uses of ''Ranunculus'' species in traditional medicines are as a

antirheumatic Disease-modifying antirheumatic drugs (DMARDs) comprise a category of otherwise unrelated disease-modifying drugs defined by their use in rheumatoid arthritis to slow down disease progression. The term is often used in contrast to nonsteroidal ...

, as a

rubefacient A rubefacient is a substance for topical application that produces redness of the skin, e.g. by causing dilation of the capillaries and an increase in blood circulation. They have sometimes been used to relieve acute or chronic pain, but there is l ...

, and to treat

intermittent fever Intermittent fever is a type or pattern of fever in which there is an interval where temperature is elevated for several hours followed by an interval when temperature drops back to normal. This type of fever usually occurs during the course of an ...

. The findings in some ''Ranunculus'' species of, for example,

protoanemonin Protoanemonin (sometimes called anemonol or ranunculol) is a toxin found in all plants of the buttercup family (Ranunculaceae). When the plant is wounded or macerated, the unstable glucoside found in the plant, ranunculin, is enzymatically bro ...

anemonin Anemonin is a compound found in plants of the buttercup family (Ranunculaceae). It is the dimerization product of the toxin protoanemonin and easily reacts with water to a dicarboxylic acid. The name of the substance comes from the plant gen ...

, may justify the uses of these species against fever, rheumatism and rubefacient in Asian traditional medicines.

Toxicity

All ''Ranunculus'' (buttercup) species are poisonous when eaten fresh, but their acrid taste and the blistering of the mouth caused by their poison means they are usually left uneaten. Poisoning in

livestock Livestock are the domesticated animals raised in an agricultural setting to provide labor and produce diversified products for consumption such as meat, eggs, milk, fur, leather, and wool. The term is sometimes used to refer solely to animals ...

can occur where buttercups are abundant in overgrazed fields where little other edible plant growth is left, and the animals eat them out of desperation. Symptoms of poisoning include bloody

diarrhea Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin wi ...

, excessive salivation,

colic Colic or cholic () is a form of pain that starts and stops abruptly. It occurs due to muscular contractions of a hollow tube (small and large intestine, gall bladder, ureter, etc.) in an attempt to relieve an obstruction by forcing content out. ...

, and severe blistering of the mouth, mucous membranes and gastrointestinal tract. When ''Ranunculus'' plants are handled, naturally occurring

ranunculin Ranunculin is an unstable glucoside found in plants of the buttercup family (Ranunculaceae). On maceration, for example when the plant is wounded, it is enzymatically broken down into glucose and the toxin protoanemonin Protoanemonin (sometimes ...

is broken down to form

, which is known to cause contact

dermatitis Dermatitis is inflammation of the skin, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened. The area of skin involved can ...

in humans and care should therefore be exercised in extensive handling of the plants. The toxins are degraded by drying, so

hay Hay is grass, legumes, or other herbaceous plants that have been cut and dried to be stored for use as animal fodder, either for large grazing animals raised as livestock, such as cattle, horses, goats, and sheep, or for smaller domesticat ...

containing dried buttercups is safe.

Fossil record

†''Ranunculus gailensis'' and †''Ranunculus tanaiticus'' seed

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

s have been described from the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Rhön Mountains, central

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

Species

References

Notes

General sources

External links

* *
All about the ''Ranunculus''

The ''Ranunculus'' home page

The Flower (''Ranunculus'') Fields of Carlsbad, CA
{{Taxonbar, from=Q146130 Ranunculaceae genera Taxa named by Carl Linnaeus