FNA: Horkelia congesta var. congesta vs. Rosaceae tribe Potentilleae

Phenology

Flowering spring–summer.

Habitat

Wet to dry remnant prairies, generally near valley bottoms, or on balds of low hills in oak-conifer woodlands, generally on volcanic soil

Elevation

80–700 m (300–2300 ft)

Distribution

OR

[BONAP county map]

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

Discussion

Of conservation concern.

Variety congesta is a component of the vanishing Willamette Prairie flora in western Oregon (T. N. Kaye, unpubl.). The variety has been extirpated from the northern part of its range in Marion, Polk, and Washington counties, and only isolated populations remain in the southern Willamette Valley, primarily in Lane County, and in the Umpqua Valley in Douglas County. A specimen from northern Josephine County (Beach 509, UC) is also referable to var. congesta, and two historic collections from the Rogue River Valley in Jackson County are intermediate between var. congesta and var. nemorosa.

(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