Spring cinquefoil

Potentilla tabernaemontani Ascherson

Plants openly matted; caudex branches elongate, slender, ˂sometimes rooting at nodes˃. Stems prostrate to decumbent, rarely weakly erect, 0.3–1.5 dm, lengths 1–2(–3) times basal leaves. Basal leaves not in ranks, palmate, 2–5(–10) cm; stipules: apex acuminate to acute, rarely obtuse; petiole 1–6 cm, long hairs common, ascending to appressed, 1–2.5 mm, weak to ± stiff, glands absent or sparse; leaflets 5–7, central oblanceolate to obovate, (0.8–)1–3 × 0.4–1.5 cm, petiolule 0–2 mm, margins flat, not lobed, distal 1/4–1/2(–2/3) evenly incised ± 1/3 to midvein, teeth 2–4(–5) per side, surfaces similar, green, hairs absent ˂especially adaxially˃ or sparse, 0.5–1.5(–2) mm, glands absent or sparse. Inflorescences 3–5(–6)-flowered. Pedicels often recurved, 1–3(–4) cm, not much longer in fruit than in flower. Flowers: epicalyx bractlets lanceolate, 3.5–5 × 1–1.5 mm, margins flat; hypanthium 2–4 mm diam.; sepals 3–5 mm, apex broadly acute to obtuse; petals yellow, 5–8(–10) × 4–6 mm; filaments 0.8–2 mm, anthers 0.5–0.8 mm; carpels 40–60, styles ± columnar, not papillate-swollen proximally, 1 mm. Achenes 1.5–2 mm. 2n = 28, 35, 42, 49, 56, 63, 70, 84 (Europe).

Flowering spring–early summer. Dry roadsides and lawns; 0–200 m; introduced; Ont.; Conn., Mich., Minn.; Europe.

The use of the name Potentilla verna here reflects the successful proposal by J. Soják (2009) to conserve P. verna with a conserved type. Alternatives in recent use include P. neumanniana Reichenbach (misapplied) and P. tabernaemontani. The species has an established horticultural presence, primarily as a ground cover, and is to be expected in North America beyond where reported here.