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Name derivation:

Common name ‘marsh marigold’.


Caltha Linneaus; 10 species descriptions are currently accepted taxonomically (Smit 1973).

Order Ranunculales;  Family Ranunculaceae

Herbaceous perennial, dicot.


Leaves round to chordate, and diplophyllic in the southern hemisphere (Schuettpelz and Hoot  2004).

Example of diplophylly in Caltha obtuse, endemic in New Zealand

(Weberling  1981)

Flowers yellow, white or pink, 5-6 petals (Fassett 1940.

Stem a rhizome with adventitious fibrous roots at periodic nodes.

Similar genera:

Trollius, Helleborus, and two species of Callianthemum were included as outgroups (Ibid.).


Mature leaves contain ‘protoanemonin’ (also called anemonol or ranunculol, C5H4O2 , systemic name5-Methylene-2(5H)-furanone’, mass 96 daltons) so are toxic to mammals.  The toxin is also listed as an antibacterial drug and antifungal agent.  It is formed as a wound response in all plants in the family Ranunculaceae.  Dessication destroys the toxin (Berger and Wachter 1998).


Globally distributed in circumboreal zone, both northern and southern hemispheres.

Based on chloroplast and nuclear DNA sequences, Caltha evolution and diversity began in the northern hemisphere and spread to the southern, probably through South America, followed by occupation Antarctica by middle Eocene (~49 mya) and eventually Australia and New Zealand (Schuettpelz and Hoot  2004).  The southern hemisphere species have diplophylly (leaves with ‘double blades’), a kind of teratological leaf shape.

Caltha palustris is a sulfide-sensitive species unable to oxidize the sulfide concentrations that develop in polluted sediments, so can be eliminated and replaced with less sensitive plants (e.g. Juncus effuses).  Sufficient iron in the sediments creates a sulfide ‘trap’ (precipitate if FeS), conserving C. palustris (Van de Welle et al.  2006).



Berger, A. and H. Wachter, eds. (1998).  Hunnius Pharmazeutisches Wörterbuch (8 ed.). Walter de Gruyter Verlag.

Fassett, N.C.  1940.  A Manual of Aquatic Plants.  University of Wisconsin Press (404 pp.).

Schuettpelz, E. and S.B. Hoot  2004.  Phylogeny and biogeography of Caltha (Ranunculaceae) based on chloroplast and nuclear DNA sequences.  American Journal of Botany 91*2):247-253.

Smit, P.G.  1973.  A revision of Caltha. Blumea 21: 119–150.

Weberling, F.  1981.  Morphologie der Blűten und der Blűtenstände. © Eugen Ulmer, Publisher.

Van der Welle, M.E.W., K. Niggebrugge, L.P.M. Lamers, and J.G.M. Roelofs  2007.  Differential responses of the freshwater wetland species Juncus effusus L. and Caltha palustris L. to iron supply in sulfidic environments.  Environmental Pollution 147(1):222-230.