46. Geranium rosthornii R. Knuth in Engler, Pflanzenr. 53(IV. 129): 180. 1912.
湖北老鹳草 hu bei lao guan cao
Geranium bockii R. Knuth; G. butuoense Z. M. Tan; G. duclouxii Yeo; G. fargesii Yeo; G. henryi R. Knuth; G. hupehanum R. Knuth; ?G. pseudofarreri Z. M. Tan; G. wilsonii R. Knuth; G. yuexiense Z. M. Tan.
Perennials. Rootstock ± horizontal, 5.2-14 mm in diam., not tuberculate, with thickened and napiform roots along rootstock. Stem 21-80 cm tall, erect, not rooting at nodes, with 0.1-0.5 mm patent to retrorse nonglandular trichomes. Stipules broadly lanceolate, distinct or connate at least at base. Leaves opposite; petiole with 0.3-1.4 mm patent to retrorse nonglandular trichomes; leaf blade 2.5-9.6 cm, palmately cleft, ratio of main sinus/middle segment length = 0.71-0.85, pilose with appressed nonglandular trichomes; segments 5, rhombic, 0.3-1.7 cm wide at base, 7-13-lobed in distal half, ratio of second sinus/middle segment length = 0.16-0.42. Cymules solitary, 2-flowered; peduncle 1.6-15.8 cm. Pedicel 0.7-4.4 cm, with 0.1-1.1 mm patent to retrorse nonglandular trichomes; bracteoles lanceolate. Sepals 6.3-7.9(-8.4) mm, mucro 0.7-3.2 mm, ratio of mucro/sepal length = 0.11-0.49, outside with 0.2-1.7 mm antrorse to patent nonglandular trichomes, inside glabrous. Petals pink to purplish, (1-)1.2-1.4 cm, erect to patent, outside basally with trichomes, inside basal 1/3-1/2 with trichomes, margin basally ciliate, apex rounded. Staminal filaments purplish, lanceolate, base slightly dilated, abaxially densely covered with 0.4-2 mm trichomes but glabrous toward tip; anthers purplish, 1.6-2.4 mm. Nectaries 5, hemispheric, abaxially glabrous, apex with a tuft of trichomes. Stigma reddish. Fruit 1.9-2.4 cm, erect when immature; mericarps smooth, with a basal callus, with 0.2-1 mm ± patent nonglandular trichomes; rostrum 1.1-1.5 cm, with a 2-3.2 mm narrowed apex; stigmatic remains 2.3-5 mm. Seeds 1.8-2.8 mm. Fl. Jun-Jul, fr. Aug-Sep.
● Forests, meadows; 800-3900 m. S Anhui (Dabie Shan, Huang Shan), S Gansu (Wenxian), Guizhou, W Henan, W Hubei, S Shaanxi, S Shandong, Sichuan, Yunnan.
This species resembles some specimens of Geranium dahuricum, although it can be distinguished by its rootstock with thickened and usually short napiform roots along the rootstock (not long and fasciculate), its leaves with a broad middle segment, its longer stipules, and its denser indumentum on petals and staminal filaments. The type of G. bockii has leaf blades with segments more rhombic than those of G. rosthornii; otherwise they are undistinguishable. It is mentioned in the original protologue that G. pseudofarreri may have glandular trichomes, which has not been observed in any specimen of G. rosthornii. Unfortunately, the original material of the former is not available, and consequently its synonymization remains provisional.