Flora of North America species comparison

Varieties 2 (2 in the flora).

Drymocallis lactea has had a well-established identity as Potentilla glandulosa var. (or subsp.) nevadensis; however, the epithet lactea has priority at species rank and avoids possible confusion with P. nevadensis Boissier. D. D. Keck (in J. Clausen et al. 1940) based his concept of P. glandulosa subsp. nevadensis on white-petaled plants with narrow inflorescences, the common form in the central Sierra Nevada and south. His map and annotations, however, include populations with yellow petals and widely branched inflorescences from northern California and adjacent Oregon. The two extremes merge in the northern Sierra Nevada, and populations in the North Coast Ranges of California also are problematic; the extremes are accordingly treated here as varieties of a single species. The inclusion by Keck of Washington in the species range might have been based on specimens here assigned to P. pseudorupestris.

Drymocallis lactea can be distinguished from sympatric species by its relatively large, overlapping petals, non-leafy inflorescences, and singly toothed leaflets. Pedicels and distal stems are usually densely short-hairy with relatively few or no glandular hairs (in contrast to D. pseudorupestris), and septate glands are usually absent from stem bases (in contrast to D. hansenii). The distinction between D. lactea and D. pseudorupestris breaks down at the margin of the species range in Nevada and Oregon.

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

Varieties 4 (4 in the flora).

Even with the removal of most of the subspecies of Potentilla glandulosa treated by Keck, Drymocallis glandulosa encompasses an inordinate range of variation. This is because of the apparently clinal variation between the coastal extreme (var. wrangelliana), with leafy inflorescences and broad cream-white petals, the montane var. reflexa, with less leafy inflorescences and narrow yellow petals, and the transitional interior var. glandulosa. Variety reflexa, in turn, intergrades in the mountains of southern California with var. viscida, which is anomalous in D. glandulosa with its narrow inflorescences and irregularly single-toothed leaflets. Variation outside of California is unclear, with no evident pattern to differences in petal size and color; these have largely been assigned to var. glandulosa.

At its most distinctive, Drymocallis glandulosa is a robust, densely glandular plant with widely branched leafy inflorescences (except var. viscida), relatively short, stout pedicels, broad sepals with rounded, mucronate tips (except var. viscida and sometimes var. reflexa) that are often significantly enlarged in fruit, and non-overlapping petals that are shorter than to scarcely equal to the sepals. The relatively large achenes are blunter and redder than those of most other species of Drymocallis, as discussed by J. Clausen et al. (1940).

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