Ficaria verna Huds. - syn.Ranunculus ficaria L. - Ranunculaceae
pilewort, lesser celandine, Scharbockskraut

Perennial herb, up to 20cm high, native to Europe, Northwest Africa, West Asia, naturalized in North America; leaves ovate-cordate, glabrous, very shiny; flowers golden yellow.

„The plant used to be known as Pilewort because it was used to treat hemorrhoids. Supposedly, the knobbly tubers of the plant resemble piles, and according to the doctrine of signatures this resemblance suggests that pilewort could be used to cure piles. The German vernacular Skorbutkraut („Scurvyherb“) derives from the use of the early leaves, which are high in vitamin C, to prevent scurvy. The plant is widely used in Russia and is sold in most pharmacies as a dried herb.
Medicines should be made from the dried herb or by heat extraction as the plant contains protoanemonin, a mild toxin. A single case was reported with acute hepatitis occurring after consuming a remedy made from lesser celandine. However, the process of heating or drying turns the toxin to anemonin which is non-toxic and has antispasmodic and analgesic properties.“
http://en.wikipedia.org/wiki/Lesser_celandine

„Protoanemonin, a disagreeable vesicant liquid, may be obtained by crushing the plant tissue of the crowfoot family. It undergoes spontaneous dimerisation in aqueous solution to yield crystalline anemonin.“
[The crystal and molecular structure of anemonin, C10H8O4., Karle, I.L., Karle, J., Acta Crystallographica, Vol.20(4), 1966, 555-559]

Flowers and leaves of Ficaria verna Huds. yielded four known flavonoid compounds including: kaempferol 3-O-beta-D-(6„-a-L-rhamnopyranosyl)-glucopyranoside (nicotiflorin), apigenin 8-C-beta-D-glucopyranoside (vitexin), luteolin 8-C-beta-D-glucopyranoside (orientin) and apigenin 8-C-beta-D-(2“-O-beta-D-glucopyranosyl)-glucopyranoside (flavosativaside).
[Flavonoids from Ficaria verna Huds., Tomczyk, M., Gudej, J., Sochacki, M., Zeitschrift fur Naturforschung. C, Journal of biosciences, Vol.57(5-6), 2001, 440-444] http://www.znaturforsch.com/ac/v57c/s57c0440.pdf?q=ficaria

Ficaria verna as Ranunculus ficaria
Lindman, C.A.M., Bilder ur Nordens Flora, vol.1 t.162 (1922-1926)
http://plantgenera.org/species.php?id_species=436237

Ficaria verna flower, Author: Andreas Kraska CC BY-SA 3.0