Potentilla sect. Brevifoliae
± erect, not flagelliform, not rooting at nodes, arising laterally to persistent basal rosettes, (0.2–)0.5–1.5(–2.5) dm, lengths 1.5–3(–4) times basal leaves.
basal not in ranks;
cauline 0–2;
primary leaves ± pinnate to subpinnate (distal leaflets ± distinct), rarely ternate, 2–7 cm;
petiole: long hairs absent or spreading, weak, glands common to abundant;
leaflets (3–)5–7, on distal 1/4 or less of leaf axis, usually overlapping, ± flabellate, margins flat, ± whole length unevenly incised 1/2 to nearly to midvein into 3+ lobes these in turn incised 1/4–1/2 to midvein, primary teeth of each lobe usually 2–3, often secondarily toothed, surfaces similar, green, not glaucous, long hairs (if present) weak, cottony hairs absent.
(1–)3–10-flowered, ± cymose, open, or solitary flowers.
straight in fruit, 0.1–1 cm, proximal not much longer than distal.
5-merous;
hypanthium 2.5–4.5 mm diam.;
petals yellow, ± obcordate, 3.5–6.5 mm, longer than sepals, apex retuse;
stamens ca. 20;
styles subapical, filiform, ± papillate-swollen at very base, if at all, 1.4–2 mm.
smooth.
Potentilla sect. Brevifoliae
Species 3 (1 in the flora).
Section Brevifoliae is primarily based on Potentilla brevifolia, distinctive in its abundant short-septate glands and the three to seven overlapping, more or less flabellate leaflets, most often in a subpinnate arrangement. Two Mexican species, P. macdonaldii B. L. Turner and P. richardii Lehmann, are included provisionally in the section. The rounded membranous stipules suggest a close relationship with sect. Aureae, especially P. cristae, which is also abundantly glandular.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
