Garland Prairie cinquefoil

Ivesia pinnatifida S. Watson, Proc. Amer. Acad. Arts 20: 364. 1885, not Potentilla pinnatifida C. Presl 1822

Plants rosetted to tufted; taproots ± fleshy-thickened. Stems decumbent to ascending, sometimes prostrate, 0.6–2.2 dm, lengths 1.5–3 times basal leaves. Basal leaves pinnate with distal leaflets ± distinct, 4–10 × 1–2(–3) cm; petiole 1–3 cm, straight hairs dense, ± appressed, 1–2 mm, stiff, cottony hairs absent, glands absent or sparse; primary lateral leaflets 5–7(–9) per side (sometimes with additional interspersed leaflets), on distal (1/2–)2/3–3/4 of leaf axis, ± overlapping, largest ones oblanceolate- to obovate-oblong, 0.5–1.5 × 0.4–0.8 cm, distal 3/4 to whole margin pinnately incised nearly to midvein, teeth (5–)7–9, linear-oblanceolate, 2–6 × 0.5–1 mm, apical tufts 1 mm, surfaces grayish green, straight hairs sparse (adaxially) to common, ± appressed, 1–2 mm, stiff, cottony hairs absent, glands absent or obscured. Cauline leaves (1–)2–3(–4). Inflorescences 3–15-flowered, ± compactly cymose, opening in fruit. Pedicels 0.7–2(–2.5) cm, straight in fruit. Flowers: epicalyx bractlets narrowly elliptic, ˂sometimes doubled˃, 2–3.5 × 1–1.5 mm; hypanthium 3–4 mm diam.; sepals 4–6 mm, apex ± acute; petals 4–5(–6) × 3–4(–5.5) mm; filaments 1–2 mm, anthers 1–1.5 mm, ˂often as long as filaments˃; carpels 8–20, styles 2 mm. Achenes 1.8 mm, ± smooth, not carunculate.

Flowering late spring–early summer. Vernally wet clay of rocky basaltic meadows, openings in pine woodlands; of conservation concern; 1900–2100 m; Ariz.

Potentilla arizonica is known only from the Garland Prairie area in Coconino County. Although commonly included within P. plattensis (for example, N. H. Holmgren 1997b; B. C. Johnston 1980; T. H. Kearney and R. H. Peebles 1951), P. arizonica differs in its longer hairs, more erect habit, more condensed inflorescences, pedicels that remain straight in fruit, and significantly larger anthers.