Geranium erianthum DC.

Leaves of Geranium erianthum permit a quick identification from G. platyanthum because they are more deeply divided. The main and the second sinus are deeper, and the middle segment is narrower at the base. Additionally, the sepal mucro is longer in G. erianthum, and trichomes of the stem and of the staminal filament are shorter. Usually G. erianthum has glandular trichomes restricted to the inflorescence.

Perennials. Rootstock ± horizontal, 5-10 mm in diam., not tuberculate, with thickened roots along rootstock. Stem 10-50 cm tall, erect, not rooting at nodes, with 0.2-0.6 mm retrorse appressed nonglandular trichomes. Stipules lanceolate, distinct. Leaves 1(or 2) alternate but opposite at inflorescence; petiole with 0.2-0.5 mm retrorse appressed nonglandular trichomes; leaf blade 3-11.7 cm, palmately cleft, ratio of main sinus/middle segment length = (0.8-)0.82-0.91, pilose with appressed nonglandular trichomes; segments 7, rhombic, 4.4-8.7(-16.9) mm wide at base, 10-34-lobed in distal half, ratio of second sinus/middle segment length = 0.18-0.35. Cymules solitary or in aggregates at apex of each branch, 2-flowered; peduncle (0-)1.1-5.5 cm. Pedicel 0.3-1.8 cm, with 0.2-0.6 mm patent to retrorse nonglandular trichomes and usually 0.3-2.5 mm patent glandular trichomes; bracteoles linear-lanceolate. Sepals 0.6-1 cm, mucro 0.9-2.7 mm, ratio of mucro/sepal length = 0.14-0.32, outside with 0.2-0.8 mm antrorse appressed nonglandular trichomes and 0.3-2 mm patent glandular trichomes, inside glabrous. Petals purplish, 1.2-1.8(-2) cm, erect to patent, outside basally with trichomes, inside glabrous, margin basally ciliate, apex rounded. Staminal filaments purplish, lanceolate, abaxially pilose and proximal half ciliate, trichomes 1.5-3.2 mm; anthers bluish, 2.1-3 mm. Nectaries 5, hemispheric, glabrous. Stigma purplish. Fruit 2.7-3.7 cm, erect when immature; mericarps smooth, with a basal callus, with 0.1-1.1 mm ± patent nonglandular trichomes and 0.8-1.4 mm patent glandular trichomes; rostrum 2.2-3 cm, with a 5-7.4 mm narrowed apex; stigmatic remains 1.6-2.3 mm. Seeds 2-2.9 mm. Fl. Jul-Aug, fr. Aug-Sep. 2n = 28.

Forests, scrub, meadows. Heilongjiang, E Jilin [Japan, Russia (Far East, Siberia); North America].

Geranium eriostemon Fischer ex Candolle var. orientale Maximowicz; G. gorbizense Aedo & Muñoz Garmendia; G. orientale (Maximowicz) Freyn (1902), not Miller (1768).