Panarctic Flora


360101 Caltha palustris L.


2n= (1) 28 (4x, x = 7). - Europe (N), Far East (N). - At least three reports for "palustris" and "sibirica". Reports of this number were 'corrected' by Löve and Löve (1975a) to 2n = 32.
(2) 32 (4x, x = 8). - Europe, Russia, Siberia, Far East, Alaska, Canada. - Numerous reports for "arctica", "palustris", and "sibirica".
(3) 48 (6x, x = 8). - Europe (N). - Löve and Löve (1948, for C. radicans).
(4) 52 54 56 (8x, x = 7). - Europe, Russia, Siberia, Far East, Alaska, Canada. - Numerous reports for "arctica", "palustris", "radicans", and "sibirica".
(5) 60. - Siberia, Canada. - Several reports for "arctica" and "palustris".
(6) 64 (8x, x = 8). - Siberia, Far East. - At least two reports for "palustris" and "sibirica".
(7) 70 72 80 (9-10x, x = 7, 8). - Siberia, Far East (N), Alaska. - At least four reports for "minor", "palustris", and "sibirica".
There are several reports of a wide range of numbers within restricted areas, e.g.: Löve and Löve (1956b, 2n = 48-80 for C. minor in Iceland); Johnson and Packer (1968, 2n = 56-70 for C. palustris s. lat. in northwestern Alaska); Chrtková and Jarolímová (1999, 2n = 32 34 34-36 44 47 56 56+6B 57 56-59 59 61 64 for C. palustris in Europe).

Geography: Circumboreal-polar.

Notes: Caltha palustris s. lat. is intricate morphologically and in ploidy levels. The majority of North American and western European authors have accepted only one species with or without races (e.g., Hultén 1968a, 1968b; Scoggan 1978c; Porsild and Cody 1980; Tutin and Akeroyd 1993a; Ford 1997a; Piirainen 2001). Russian authors have mostly accepted three or more species, sometimes with races, in an arctic context under the names C. arctica, C. caespitosa, C. palustris (s. str.), C. radicans, C. sibirica, and C. violacea (e.g., Tolmachev 1955, 1971b; Friesen 1993; Luferov 1995; Tzvelev 2000a; Rebristaya's PAF proposal supported by Yurtsev). A major revision of the genus is Smit (1973), based on morphology and cytology, but with little focus on the infraspecific variation in C. palustris s. lat. The phylogenetic study mentioned above (Schuettpelz and Hoot 2004) did not apply molecular markers resolving the C. palustris group.

There are probably two base chromosome numbers, x = 7 and 8, and each of the proposed taxa are mostly reported with 3-4 ploidy levels from 4x to 9-10x. Löve and Löve (1975a) accepted three species to reach the Arctic: an, according to them, uniformly tetraploid C. palustris with an, also according to them, Eurasian subsp. palustris and a northwestern North American subsp. asarifolia; a hexaploid to high polyploid C. minor with a nearly circumpolar subsp. arctica (including C. caespitosa); and a 7-10-ploid Siberian C. sibirica. They reported the base number to be 2n = 8. This is a nice solution but not well supported by facts, as shown by a few examples. A multitude of numbers higher than tetraploid have been reported within temperate European C. palustris (subsp. palustris in the Löves' meaning), all omitted by Löve and Löve (1975a). They referred many high-polyploid numbers for their C. minor subsp. arctica from areas well outside the geographical range they accepted for this taxon but inside that of C. palustris s. str. The single tetraploid number referred by them for their C. palustris subsp. asarifolia (Johnson and Packer 1968, from Ogotoruk Creek in northwestern Alaska) was made ca. 1000 km north of the accepted northern limit of this subspecies but inside that of their C. minor subsp. arctica. However, Johnson and Packer (1968) claimed from morphological evidence that two taxa of Caltha occur in the Ogotoruk Creek area, but it is improbable that subsp. asarifolia is one of these.

Piirainen (2001) assigned the name C. minor to the species and not to any of the two subspecies. He claimed that the name was not assignable with any certainty to the major northern plant or race (i.e., C. arctica or subsp. radicans), as done by Löve and Löve (1975a).

The complicated ploidy situation might indicate a reticulum not readily resolved in formal taxonomy. For a very critical view concerning the possibility of an infraspecific taxonomy of C. palustris s. lat., see Jalas and Suominen (1989: 42-43). We fully accept only one species with two subspecies - C. palustris subsp. palustris and subsp. radicans - but in addition enter three races provisionally: var. sibirica, subsp. caespitosa, and subsp. violacea.

Higher Taxa