17. Geranium thunbergii Siebold ex Lindley & Paxton, Paxton’s Fl. Gard. 1: 186. 1851.
中日老鹳草 zhong ri lao guan cao
Geranium nepalense Sweet var. thunbergii (Siebold ex Lindley & Paxton) Kudô.
Perennials. Rootstock vertical, 2-10 mm in diam., not tuberculate, without thickened roots. Stem 20-70 cm tall, trailing or ascending, sometimes rooting at nodes, with 0.3-1.4 mm patent or retrorse appressed nonglandular trichomes and sometimes 0.8-1.3 mm patent glandular trichomes. Stipules lanceolate to subulate, distinct. Leaves opposite; petiole with 0.3-1.2 mm patent to retrorse nonglandular trichomes and sometimes 0.5-1.2 mm patent glandular trichomes; leaf blade 2.4-6.4 cm, palmately cleft, ratio of main sinus/middle segment length = 0.73-0.91, pilose with appressed nonglandular trichomes; segments 5, rhombic, 4-12 mm wide at base, 5-8-lobed in distal half, ratio of second sinus/middle segment length = 0.11-0.21. Cymules solitary, 2-flowered; peduncle 2.2-13.9 cm. Pedicel 0.8-3.3 cm, with 0.2-1 mm patent nonglandular trichomes and usually 0.6-1.1 mm patent glandular trichomes; bracteoles linear-lanceolate. Sepals 5.1-8.1 mm, mucro 0.8-1.9 mm, ratio of mucro/sepal length = 0.12-0.25, outside with 0.1-0.9 mm patent to antrorse nonglandular trichomes and 0.2-1.2 mm patent glandular trichomes, inside glabrous. Petals white or purplish, (6.8-)7.3-8.3(-9) mm, erect to patent, outside glabrous, inside basally with trichomes, margin basally ciliate, apex rounded or retuse. Staminal filaments whitish, lanceolate with an abruptly narrowed apex, abaxially pilose and proximal half ciliate, trichomes 0.1-0.7 mm; anthers bluish, 0.8-1.1 mm. Nectaries 5, hemispheric, glabrous. Stigma pink. Fruit 1.9-2.7 cm, erect when immature; mericarps smooth, with a basal callus, with 0.2-0.7 mm ± patent nonglandular trichomes and 0.6-1.5 mm glandular trichomes; rostrum 1.3-2 cm, with a 0.5-1.8 mm narrowed apex; stigmatic remains 1.6-2.3 mm. Seeds 1.7-2.2 mm. Fl. Apr-Sep, fr. May-Oct. 2n = 28.
Roadsides, meadows, weedy areas; near sea level to 2200 m. Anhui, Fujian, Guangdong, Hebei, Hubei, Hunan, Jiangxi, Shaanxi, Taiwan, Zhejiang [Japan, Korea, Russia].
This species has sometimes been submerged in Geranium nepalense. However, it is well characterized by the presence of glandular trichomes (sometimes restricted to sepals) and by longer petals, sepals, and fruit. Additionally, leaves of G. thunbergii have few lobes, and its mericarps are darker. Distribution of G. thunbergii seems to be more eastern than those of G. nepalense, being alone in Taiwan, Japan, and Korea.