Potentilla sect. Aureae
Rosaceae tribe Potentilleae
usually ascending to erect, sometimes prostrate to decumbent or spreading, not flagelliform, not rooting at nodes (except P. verna), lateral to persistent basal rosettes, 0.1–2(–3) dm, lengths 1–3(–4) times basal leaves.
basal sometimes 2-ranked;
cauline 0–2(–3);
primary leaves ternate or palmate, (0.5–)1–12(–20) cm;
petiole: long hairs absent or spreading to ascending, weak to ± stiff, glands usually absent or sparse, sometimes abundant;
leaflets 3–7, at tip of leaf axis, overlapping or not, broadly oblanceolate or obtriangular to flabellate, margins flat to revolute, distal 1/4–3/4+ evenly to unevenly incised 1/4–1/2 to midvein, sometimes 3–5-lobed 1/2–3/4 to midvein as well, primary teeth (1–)2–5(–7) per side or per lobe, surfaces ± similar, abaxial pale to dark green, rarely grayish, brownish, or reddish, cottony hairs absent, adaxial green to dark green, rarely brownish or reddish, sometimes ± glaucous (P. grayi), long hairs (if present) soft to weak, sometimes stiff.
alternate, rarely opposite, pinnately (palmately) compound (simple in Alchemilla, Aphanes, and Chamaerhodos);
stipules persistent (absent in Chamaerhodos), adnate to petiole;
venation pinnate or palmate.
1–6(–12)-flowered, ± cymose, ± to very open, or solitary flowers.
usually straight in fruit (often recurved in P. verna), (0–)0.2–3(–9) cm, proximal usually not much longer than distal (sometimes longer in fruit).
5-merous;
hypanthium 2–7 mm diam.;
petals pale to dark yellow, mostly ± obcordate (to orbiculate in P. elegans), (2–)3–10(–12) mm, usually longer than sepals, apex usually ± retuse;
stamens ca. 20;
styles subapical, columnar, filiform, or tapered, not, scarcely, or ± papillate-swollen in proximal 1/5–1/2, 0.8–2.5 mm.
perianth and androecium perigynous;
epicalyx bractlets present, sometimes absent;
hypanthium usually patelliform, cupulate, or campanulate, sometimes turbinate, saucer-shaped, flat-bottomed, or subglobose to ellipsoid or ovoid;
torus flat to conic or turbinate, enlarged (absent or reduced in Alchemilla, Aphanes, and Chamaerhodos);
carpels 1–260, styles basal or lateral to subterminal, distinct;
ovules 1(or 2), basal.
aggregated achenes (achenes in Alchemilla and Aphanes);
torus sometimes fleshy;
styles deciduous or persistent, not elongate.
± smooth.
Potentilla sect. Aureae
Rosaceae tribe Potentilleae
Species ca. 30 (10 in the flora).
The circumscription of sect. Aureae used here largely follows that of B. C. Johnston (1985), except that Potentilla sierrae-blancae is placed in sect. Concinnae and P. rubella and P. stipularis are in sect. Chrysanthae. Other treatments (for example, P. A. Rydberg 1908d; T. Wolf 1908) split the species included here in two groups and/or recombine them with species in other sections, notably sect. Ranunculoides (Th. Wolf) Juzepczuk.
Since Potentilla glaucophylla (sect. Graciles) and P. cottamii (sect. Subviscosae) are sometimes identified as members of sect. Aureae, they are included herein and key out in the third and twelfth couplets, respectively.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Genera 14–22, species ca. 860 (14 genera, 189 species, including 1 hybrid, in the flora area).
The base chromosome number for Potentilleae is mostly x = 7 (8 in Alchemilla and Aphanes; 14 in Comarum).
Variation in the number of genera recognized in Potentilleae is due to differences in generic delimitation between D. Potter et al. (2007) and the authors of Potentilla and segregates here (see 9. Ivesia and 8. Potentilla for discussion). In the former, Duchesnea, Horkelia, Horkeliella, and Ivesia are included within Potentilla. Likewise, Aphanes is included within Alchemilla by Potter et al. while it is kept distinct here.
Potentilla and its segregates and Fragaria are host to Phragmidium rusts, but not the other genera of the tribe.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Basal leaflets (3–)4–7 | → 2 |
1. Basal leaflets 3 | → 4 |
2. Basal leaves not in ranks; stems usually prostrate to decumbent, rarely weakly erect; caudex branches elongate and slender; pedicels often recurved; introduced. | P. verna |
2. Basal leaves 2-ranked; stems ascending to erect; caudex branches usually short and stout, sometimes elongate and slender; pedicels straight; native | → 3 |
3. Leaves glaucous, ± blue-green; styles 1.5–2.5(–3) mm; sepals: apex acute to short acuminate; w North America, Greenland. | P. glaucophylla (sect. Graciles) |
3. Leaves not glaucous, green; styles 1–1.6 mm; sepals: apex broadly acute; ne Canada, Greenland. | P. crantzii |
4. Central leaflets deeply 3–5-lobed (sinuses extending 1/2 to nearly to midvein), lobes unevenly incised 1/4–1/2 to midvein, teeth (1–)2–5 per lobe, glands sparse to abundant | → 5 |
4. Central leaflets not or shallowly lobed (sinuses extending less than 1/2 to midvein), evenly or unevenly incised 1/4–1/2 to midvein, teeth 2–7 per side, glands absent or sparse to common | → 6 |
5. Styles 1.3–2 mm; stems 0.3–2 dm; sepals 3–5 mm; nw California. | P. cristae |
5. Styles 0.7–0.9 mm; stems 0.1–0.5 dm; sepals 2.2–2.5 mm; arctic. | P. elegans |
6. Leaflet and epicalyx bractlet margins revolute; British Columbia, Alaska | → 7 |
6. Leaflet and epicalyx bractlet margins flat, sometimes slightly or ± revolute; North America | → 8 |
7. Petals 9–12 mm; caudex branches stout (diam. 1–2 cm, including old leaf-bases); filaments (2–)2.8–3.2 mm; styles 1.7–2 mm; 0–10 m. | P. fragiformis |
7. Petals 4–8 mm; caudex branches slender to ± stout (diam. 0.5–1 cm, including old leaf-bases); filaments 1.2–2 mm; styles 0.8–1.2 mm; 100–1100 m. | P. nana |
8. Styles 1–2.5 mm; filaments 1–3 mm | → 9 |
8. Styles 0.6–1 mm; filaments 0.5–1(–1.5) mm | → 11 |
9. Leaflet margins usually unevenly incised, teeth 3–7 per side, often secondarily toothed. | P. flabellifolia |
9. Leaflet margins evenly incised, teeth (2–)3–4(–5) per side, not secondarily toothed | → 10 |
10. Petioles: long hairs 1–2.5 mm; central leaflets: petiolules 0–1 mm; Greenland, ne Canada. | P. crantzii |
10. Petioles: long hairs 0.5–1 mm; central leaflets: petiolules (1–)3–10 mm; California. | P. grayi |
11. Epicalyx bractlets 3.5–7 mm; petals 4–9 mm. | P. hyparctica |
11. Epicalyx bractlets (1.8–)2–2.5(–3) mm; petals 2–3 mm | → 12 |
12. Epicalyx bractlets 1/2–3/4 as long as sepals; inflorescences 1–4-flowered; Great Basin. | P. cottamii (sect. Subviscosae) |
12. Epicalyx bractlets ± equal to sepals; inflorescences 1(–2)-flowered; New England. | P. robbinsiana |
1. Shrubs; leaf lobe margins entire; achenes hirsute. | Dasiphora |
1. Herbs, perennial, sometimes annual or biennial, or subshrubs; leaf lobe margins or apices ± toothed, sometimes entire; achenes glabrous (sometimes ± hairy) | → 2 |
2. Petals 0, sepals 4; achenes 1, enclosed in dry, urceolate or subglobose to ellipsoid or ovoid hypanthia | → 3 |
2. Petals and sepals usually 5; achenes 1–260, usually aggregated (sometimes on elongating tori), usually in (± open) patelliform, cupulate, campanulate, or turbinate hypanthia (not enclosed in dry hypanthium) | → 4 |
3. Herbs perennial; leaves basal, blades reniform to orbiculate, palmately lobed, sometimes palmately compound; stamens 4. | Alchemilla |
3. Herbs annual; leaves cauline, blades cuneate, deeply divided into segments, each lobed; stamen 1(or 2). | Aphanes |
4. Leaves all or mostly basal or proximal (if cauline, deeply pinnatifid), ternate or 2–4-ternate (sometimes simple and coarsely toothed apically in Sibbaldia) | → 5 |
4. Leaves basal or cauline, the latter usually reduced distally, odd-pinnate to palmate, rarely ternate or ± bipinnate | → 9 |
5. Tori becoming red and fleshy in fruit; leaf margins serrate to crenate | → 6 |
5. Tori hemispheric (not enlarged or fleshy) in fruit or absent; leaf margins entire or (2–)3(–5)-toothed apically | → 7 |
6. Leaves ± doubly serrate or crenate; stolons leafy; inflorescences: flowers solitary, axillary at stolon nodes; petals yellow. | Duchesnea |
6. Leaves serrate to crenate; stolons not leafy; inflorescences 1–10-flowered, cymes, axillary from leaf rosettes; petals usually white. | Fragaria |
7. Leaves pinnately compound or simple and deeply pinnatifid, margins entire, stipules absent. | Chamaerhodos |
7. Leaves ternate, margins toothed apically, stipules persistent | → 8 |
8. Petals ± yellow; stamens 5. | Sibbaldia |
8. Petals usually white; stamens 20(–30). | Sibbaldiopsis |
9. Petals deep red to purple, rarely pink, shorter than sepals; tori enlarged and spongy at maturity; horizontal stems sometimes floating, wetland habitats. | Comarum |
9. Petals yellow to white, rarely pink or red (then equal to or longer than sepals); tori not enlarged and spongy at maturity; stems erect to decumbent, not horizontal or floating even if in wetlands | → 10 |
10. Anthers dehiscing by continuous marginal slit (with a single theca); styles sub-basal. | Drymocallis |
10. Anthers dehiscing longitudinally; styles subterminal to lateral | → 11 |
11. Hypanthium patelliform to campanulate or cupulate to turbinate (not flat-bottomed); filaments not forming tube; petals white to yellow, sometimes reddish or pink tinged | → 12 |
11. Hypanthium ± cupulate or bluntly campanulate and flat-bottomed; filaments forming tube; petals usually white, sometimes pink-tinged, rose-veined, or cream | → 13 |
12. Plants not aromatic; leaves ± cordate or reniform to narrowly elliptic in outline, leaflets 3–15(–41); petals oblanceolate or obovate to obcordate to nearly round, rarely elliptic; carpels 3–260. | Potentilla |
12. Plants often aromatic; leaves planar to cylindric, leaflets (3–)7–161; petals linear or narrowly oblanceolate to obovate, sometimes obcordate; carpels 1–20(–40). | Ivesia |
13. Stamens 10; leaflets (3–)5–41. | Horkelia |
13. Stamens 20; leaflets 30–70. | Horkeliella |
