Description from Flora of China
Ranunculus japonicus Thunberg var. smirnovii (Ovczinnikov) L. Liou.
Herbs perennial. Roots fibrous, subequally thick. Stems ca. 50 cm, densely spreading hirsute, branched. Basal leaves ca. 10; petiole 10--20 cm, densely spreading hirsute; blade 3-lobed, cordate-pentagonal, 5--10 × 7--13 cm, papery, abaxially puberulent, base cordate, margin incised-dentate; central lobe rhombic or broadly rhombic, acute, 3-lobed, incised-dentate; lateral lobes obliquely flabellate, unequally 2-cleft slightly beyond middle. Lower stem leaves similar to basal ones; upper stem leaves subsessile or sessile, 3--5-sect, segments oblong-rhombic. Compound monochasium terminal, ca. 10-flowered; bracts leaflike, 3-sect. Flowers 1.6--1.8 cm in diam. Pedicel 1--4 cm, densely appressed puberulent. Receptacle glabrous. Sepals 5, elliptic-ovate, 4--5 mm, abaxially appressed puberulent. Petals 5, broadly obovate, 8--10 × 7--8 mm, nectary pit covered by a scale, apex rounded. Stamens numerous; anthers oblong. Aggregate fruit subglobose, ca. 5 mm in diam.; carpels numerous. Achene obliquely obovate, ca. 2 × 1.8 mm, glabrous, narrowly marginate; style persistent, ca. 0.3 mm. Fl. Jul--Aug.
Meadows, forests. NE Nei Mongol [Russia (E Siberia)].