Geranium christensenianum Hand.-Mazz.

This species has leaf blades mostly with 3 segments, although some cultivated specimens could have basal leaves with 5 segments. According to Yeo (Hardy Geraniums, 92. 2002), Geranium christensenianum has been found in Sichuan (Longzhou Shan) and from this source is cultivated in United States and United Kingdom.

Perennials. Rootstock 5-6 mm in diam., not tuberculate, with many fibrous roots. Stem 48-100 cm tall, trailing, rooting at nodes, with 0.3-1.3 mm patent nonglandular trichomes and 0.5-1.1 mm patent glandular trichomes. Stipules lanceolate, distinct. Leaves opposite; petiole with 0.2-1 mm patent nonglandular trichomes and 0.2-1.4 mm patent glandular trichomes; leaf blade 3.9-5.3 cm, palmately cleft, ratio of main sinus/middle segment length = 0.72-0.78, pilose with appressed nonglandular trichomes and ± patent glandular trichomes; segments 3(or 5), rhombic, 8.6-10.7 mm wide at base, 5-13-lobed in distal half, ratio of second sinus/middle segment length = 0.15-0.21. Cymules solitary, 2-flowered; peduncle 2.1-15.3 cm. Pedicel 0.8-1.7 cm, with 0.2-0.6 mm patent nonglandular trichomes and 0.3-1.2 mm patent glandular trichomes; bracteoles lanceolate. Sepals 0.8-1.2 cm, mucro 1.6-2.7 mm, ratio of mucro/sepal length = 0.18-0.22, outside with 0.2-0.8 mm antrorse to patent nonglandular trichomes and 0.5-1.6 mm ± patent glandular trichomes, inside glabrous. Petals whitish with fine dark purple veins, 1.2-1.4(-1.6) cm, erect to patent, outside basally with trichomes, margin basally ciliate, apex rounded. Staminal filaments blackish except base, lanceolate, abaxially densely covered with 0.2-0.8 mm trichomes but glabrous toward tip; anthers black, 2.1-2.5 mm. Nectaries 5, hemispheric, abaxially glabrous, apex with a tuft of trichomes. Stigma blackish. Fruit ca. 3.2 cm, erect when immature; mericarps smooth, with a basal callus, with 0.3-1 mm ± patent nonglandular trichomes and 0.6-1.5 mm patent glandular trichomes; rostrum 2.1-2.2 cm, with a 4-5 mm narrowed apex; stigmatic remains 5.9-6.2 mm. Seeds unknown. Fl. Jul-Aug, fr. Sep-Oct.

SW Sichuan (Liangshan), NE Yunnan.

● Forests, scrub, meadows; 2300-2800 m.

Geranium christensenianum là một loài thực vật có hoa trong họ Mỏ hạc. Loài này được Hand.-Mazz. mô tả khoa học đầu tiên năm 1933.

大姚老鹳草（学名：Geranium christensenianum）是牻牛儿苗科老鹳草属的植物，为中国的特有植物。分布在中国大陆的云南等地，生长于海拔2,300米至2,800米的地区，见于林下、灌丛和向阳山坡，目前尚未由人工引种栽培。