1	Flowering stems erect or ascending.		(2)
+	Flowering stems prostrate or horizontally creeping.		(5)
2 (1)	Leaves pinnate with 2 or 3(or 4) pairs of leaflets.		81 P. fragarioides
+	Leaves 3-foliolate.		(3)
3 (2)	Plants stellate hairy throughout.		80 P. acaulis
+	Plants pilose or glabrescent throughout, not stellate hairy.		(4)
4 (3)	Leaflets abaxially pilose or glabrescent; flowers 1–2 cm in diam.; epicalyx segments oblong, apex rounded; anthers basifixed, subglobose or ovoid, minute.		79 P. gelida
+	Leaflets abaxially spreading strigose or densely hairy; flowers 0.8–1 cm in diam.; epicalyx segments lanceolate, apex acuminate; anthers dorsifixed, ellipsoid, larger.		82 P. freyniana
5 (1)	Leaves palmately 5-foliolate.		(6)
+	Leaves 3-foliolate.		(7)
6 (5)	Flowers 1.5–2.2 cm in diam.; epicalyx segments usually broad, enlarged and leaflike after anthesis, apex obtuse or acute; leaflets obovate-oblong, margin regularly obtusely or rarely acutely serrate.		84 P. reptans
+	Flowers 1–1.5 cm in diam.; epicalyx segments narrow, not enlarged after anthesis, apex acuminate, rarely acute; leaflets oblong-lanceolate, margin irregularly acutely or acuminately serrate.		86 P. flagellaris
7 (5)	Lateral leaflets 2-lobed or 2-parted.		84 P. reptans
+	Leaflets neither lobed nor parted.		(8)
8 (7)	Leaflets rhombic-ovate, rhombic-obovate, or broadly elliptic, margin sharply serrate (teeth fasciated ovate) or doubly serrate; stolons curved and zigzagged; flowers 1.5–2 cm in diam.		83 P. rosulifera
+	Leaflets obovate or elliptic, margin regularly acutely or obtusely serrate; stolons not curved nor zigzagged; flowers 0.7–1 cm in diam.		85 P. simulatrix