FNA: Ivesia gordonii var. alpicola vs. Rosaceae tribe Potentilleae

Phenology

Flowering summer.

Habitat

Dry grassy areas on talus, or gravelly or rocky slopes and ridges, in subalpine and alpine montane conifer woodlands, alpine tundra

Elevation

2100–3300 m (6900–10800 ft)

Distribution

CA; ID; MT; OR; WA

North America; Mexico; Central America; South America; West Indies; Bermuda; Eurasia; Africa; Atlantic Islands; Pacific Islands; Australia

Discussion

P. A. Rydberg (1898) used var. alpicola (as Horkelia gordonii var. alpicola) for compact, high-elevation plants throughout the range of Ivesia gordonii. As circumscribed here, var. alpicola is restricted to plants occurring disjunctly in an arc around the northwestern part of the species range. Populations occur in the northern Coast Ranges and central Sierra Nevada of California, sporadically to Mount Adams and the Wenatchee Mountains in Washington, and from there to the mountains of central Idaho and the Bitterroot Range of Montana. The variety is also disjunct on the Owyhee Mountains of southwestern Idaho.

Plants of var. alpicola average shorter than those of var. gordonii, which occurs farther east and south. In var. alpicola, stems with only glandular indumentum are common; such stems are rare in var. gordonii. Unlike those of var. gordonii, the leaflets of var. alpicola are frequently glandular with only marginal hairs.

(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.)

Key

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