Description from Flora of China
Geranium calanthum Handel-Mazzetti; G. forrestii R. Knuth; G. kariense R. Knuth; G. limprichtii Lingelsheim & Borza.
Perennials. Rootstock ± horizontal, 0.7-1.8 cm in diam., not tuberculate, with thickened roots along rootstock. Stem 23-85 cm tall, erect, not rooting at nodes, with 0.2-0.7 mm retrorse to patent nonglandular trichomes and rarely 1-1.1 mm patent glandular trichomes. Stipules lanceolate, connate at least at base. Leaves opposite; petiole with 0.3-0.6 mm patent to retrorse nonglandular trichomes and rarely 0.4-0.5 mm patent glandular trichomes; leaf blade 3.2-10.2 cm, palmately cleft, ratio of main sinus/middle segment length = 0.81-0.93, pilose with appressed nonglandular trichomes; segments 5, rhombic, 3.4-11 mm wide at base, 9-26-lobed in distal half, ratio of second sinus/middle segment length = 0.13-0.32. Cymules solitary or in aggregates at apex of each branch, 2-flowered; pedun cle 2-11.9 cm. Pedicel 0.7-3.4 cm, with 0.2-0.5 mm patent to retrorse nonglandular trichomes and sometimes 0.9-2.1 mm patent glandular trichomes; bracteoles filiform. Sepals 6.5-10 mm, mucro 0.9-2.6 mm, ratio of mucro/sepal length = 0.12-0.34, outside with 0.3-1.1 mm antrorse ± appressed nonglan dular trichomes and sometimes 0.6-2.2 mm patent glandular trichomes, inside glabrous. Petals blackish red to pink with a whitish base, (6.1-)8-9.8(-12.3) mm, reflexed, basally with trichomes sometimes outside and also usually inside, margin basally with a dense tuft of trichomes, apex rounded. Staminal filaments reddish, lanceolate, abaxially sparsely pilose and proximal half ciliate, trichomes 0.3-1.2 mm; anthers blackish, 1.9-2.5 mm. Nectaries 5, hemispheric, abaxially glabrous, apex with a tuft of trichomes. Stigma reddish. Fruit 2.4-3 cm, nodding when immature; mericarps smooth, with a basal callus, with 0.2-0.8 mm ± patent nonglandular trichomes; rostrum 1.7-2.2 cm, with a 3.6-6.2 mm narrowed apex; stigmatic remains 1.8- 3.4 mm. Seeds 2.2-2.8 mm. Fl. Jun-Aug, fr. Aug-Oct.
Petals of Geranium delavayi are shorter than in G. refractum and G. pogonanthum, and they have a whitish base. Petals are sometimes blackish, as in G. sinense, but with abundant trichomes inside at base. The almost glabrous filaments are also useful to differentiate G. delavayi from G. pogonanthum, and filiform bracteoles from G. refractum. The glandular trichomes of the inflorescence, when present, are similar to those of G. sinense. Geranium calanthum is sometimes differentiated by petals pale yellow. However, neither original description nor type specimen support this opinion. Geranium kariense and G. limprichtii are differentiated by the nonglandular pedicels and petal size, which are variable features in G. delavayi.
● Forest margins, scrub, meadows; 2300-4100 m. S Sichuan, Yunnan.