The genus is distributed worldwide, primarily in temperate and montane regions.[2] The familiar and widespread buttercup of gardens throughoutNorthern Europe (and introduced elsewhere) is the creeping buttercupRanunculus repens, which has extremely tough and tenacious roots. Two other species are also widespread, the bulbous buttercupRanunculus bulbosus and the much taller meadow buttercupRanunculus acris. In ornamental gardens, all three are often regarded asweeds.
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 subgenusBatrachium), which grow in still or running water, are sometimes treated in a separate genusBatrachium (fromGreekβάτραχοςbátrakhos, "frog"). They have two different leaf types, thread-like leaves underwater and broader floating leaves. In some species, such asR. aquatilis, a third, intermediate leaf type occurs.
Buttercups are found in both hemispheres on all continents aside from Antarctica, and are primarily found in temperate or montane habitats. They likely originated in northern Eurasia during the lateEocene orOligocene and rapidly radiated up to the present, dispersing worldwide.[4][5] Fossil evidence suggests that despite no longer occurring there, they inhabited Antarctica up to the mid-latePliocene, even while glaciations were rapidly altering the landscape.[6]
Buttercups are mostlyperennial, but occasionally annual orbiennial,herbaceous, 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.[citation needed]
The leaves lackstipules, havepetioles, arepalmately veined, entire, more or less deeply incised, or compound, and leaflets or leaf segments may be very fine and linear in aquatic species.[citation needed]
Thehermaphrodite flowers are single or in acyme, have usually five (but occasionally as few as three or as many as seven)sepals and usually, five yellow, greenish or whitepetals that are sometimes flushed with red, purple or pink (but the petals may be absent or have a different, sometimes much higher number).[citation needed]
At the base of each petal is usually onenectary 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 yellowpollen. The sometimes few but mostly many green or yellowcarpels are not fused and are also arranged in a spiral, mostly on a globe or dome-shapedreceptacle.[citation needed]
The petals of buttercups are often highlylustrous, especially in yellow species, owing to a special coloration mechanism: the petal's upper surface is very smooth causing a mirror-like reflection.[10][11] The flash aids in attractingpollinating insects andtemperature regulation of the flower's reproductive organs.[10] The reflective quality of the buttercup's petals is mentioned in British folklore; if one holds a buttercup underneath theirchin, the light reflecting onto the chin indicates that they likebutter.[12][13][14]
The genus nameRanunculus isLate Latin for "little frog", the diminutive ofrana.[16] This probably refers to many species being found near water, like frogs.[15]
The common namebuttercup may derive from a false belief that the plants givebutter its characteristic yellow hue[citation needed] (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.[17] In ancient Rome, a species of buttercup was held to the skin by slaves attempting to remove forehead tattoos made by their owners.[18]: 106
In the interior of the Pacific Northwest of the United States, the buttercup is called "Coyote's eyes"—ʔiceyéeyenm sílu inNez Perce[19] andspilyaynmí áčaš inSahaptin.[20] In the legend,Coyote 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.[citation needed]
The most common uses ofRanunculus species in traditional medicines are as anantirheumatic, as arubefacient, and to treatintermittent fever. The findings in someRanunculus species of, for example,protoanemonin,anemonin, may justify the uses of these species against fever, rheumatism and rubefacient in Asian traditional medicines.[22]
AllRanunculus (buttercup) species arepoisonous when eaten fresh, but their acrid taste and the blistering of the mouth caused by their poison means they are usually left uneaten. Poisoning inlivestock 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 bloodydiarrhea, excessivesalivation,colic, and severe blistering of the mouth, mucous membranes and gastrointestinal tract. WhenRanunculus plants are handled, naturally occurringranunculin is broken down to formprotoanemonin, which is known to cause contactdermatitis in humans and care should therefore be exercised in extensive handling of the plants.[23] The toxins are degraded by drying, sohay containing dried buttercups is safe.[24]
^ab"Ranunculus L., Sp. Pl.: 548 (1753)".Plants of the World Online. Board of Trustees of the Royal Botanic Gardens, Kew. 2022. Retrieved6 November 2022.
^abc"Ranunculus L."World Flora Online. World Flora Online Consortium. 2022. Retrieved6 November 2022.
^Emadzade, Khatere; Gehrke, Berit; Peter Linder, H.; Hörandl, Elvira (2011). "The biogeographical history of the cosmopolitan genus Ranunculus L. (Ranunculaceae) in the temperate to meridional zones".Molecular Phylogenetics and Evolution.58 (1):4–21.Bibcode:2011MolPE..58....4E.doi:10.1016/j.ympev.2010.11.002.ISSN1055-7903.PMID21078403.
^Kamen, Deborah (2010). "A corpus of inscriptions: Representing slave marks in antiquity".Memoirs of the American Academy in Rome.55:95–110.ISSN0065-6801.JSTOR41419689.
^Aoki, Haruo (1994).Nez Perce dictionary. Berkeley, CA: University of California Press. pp. 641, 1007.ISBN978-0-520-09763-6.
^Rude, Noel (2014).Umatilla dictionary. Seattle, WA: University of Washington Press. pp. 54, 275.ISBN978-0-295-99428-4.
^Emadzade, K.; Lehnebach, C.; Lockhart, P.; Hörandl, E. (2010). "A molecular phylogeny, morphology and classification of genera of Ranunculeae (Ranunculaceae)".Taxon.59 (3):809–828.Bibcode:2010Taxon..59..809E.doi:10.1002/tax.593011.
^Aslam, M.S.; Choudhari, B.S.; Uzair, M.; Ijaz, A.S. (2012). "The genusRanunculus: A phytochemical and ethnopharmacological review".International Journal of Pharmacy and Pharmaceutical Sciences.4 (5):15–22.
"GRIN Species Records ofRanunculus".Germplasm Resources Information Network (GRIN). United States Department of Agriculture, Agricultural Research Service, Beltsville Area. Retrieved8 January 2008.
