Flora of North America species comparison

Varieties 3 (3 in the flora).

Potentilla concinna is a relatively widespread, low-growing, early-blooming species with palmate to subpalmate, abaxially cottony leaves. Flowers often appear before leaves are fully expanded. The three varieties treated here have some level of biogeographic identity and are, therefore, given provisional taxonomic recognition. Some treatments have also included P. bicrenata, P. johnstonii, and P. macounii as varieties of P. concinna. Two Mexican species, P. leonina Standley and P. oblanceolata Rydberg, have also been treated as varieties of P. concinna by J. Soják (2006); they are retained as distinct species here, pending further research on Mexican Potentilla. Two other erstwhile varieties of P. concinna are now placed in separate sections: var. modesta (Rydberg) S. L. Welsh & B. C. Johnston (misapplied) in sect. Rubricaules as P. modesta, and var. rubripes (Rydberg) C. L. Hitchcock in sect. Subjugae, intermediate between P. saximontana and P. subjuga. Potentilla concinnaeformis Rydberg, considered to be a close relative of P. concinna by I. W. Clokey (1939), is more likely a hybrid between P. glaucophylla (sect. Graciles) and P. hippiana (sect. Leucophyllae). Hybrids also occur with P. multisecta, and probably other species as well.

Potentilla concinna was first described in 1818 as P. humifusa Nuttall, a later homonym for P. humifusa Willdenow.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Subspecies 4 or 5 (4 in the flora).

Potentilla anserina is polymorphic in most features, especially in hairiness, but also in size and in degree of dissection of leaflets, epicalyx bractlets, and sepals. While most of the variation described by A. G. Blytt (1906) is taxonomically insignificant, A. Rousi (1965) found support for three northern races: subspp. anserina, egedei, and pacifica. He also suggested that P. yukonensis Hultén might qualify as a separate subspecies. This treatment follows J. Soják (1994) in accepting four northern subspecies of P. anserina, all present in North America.

A. Rousi (1965) demonstrated partial interfertility between the races of Potentilla anserina, which form intermediates in all zones of contact. The distinctness of the four races, in spite of intermediates, is upheld by being partly allopatric and occupying different habitats where they are sympatric. As partly interfertile parapatric entities, they are best treated as subspecies.

The vast majority of chromosome counts are tetraploid. Tetraploid plants (2n = 28) are fully fertile; hexaploids (2n = 42) are largely pollen and seed sterile; pentaploids (2n = 35) are probably occasional hybrids (S. Erlandsson 1942, 1942b; A. Rousi 1965). A. Kurtto et al. (in J. Jalas et al. 1972+, vol. 13) considered numbers above tetraploid level as cases of occasional autopolyploidy.

(Discussion copyrighted by Flora of North America; reprinted with permission.)