灰岩紫地榆 hui yan zi di yu

Geranium franchetii var. glandulosum Z. M. Tan; G. strigellum R. Knuth.

Perennials. Rootstock ± horizontal, 4.5-7.9 mm in diam., not tuberculate, with thickened roots along rootstock. Stem 25-60 cm tall, erect, not rooting at nodes, with scattered 0.2-0.5 mm retrorse appressed nonglandular trichomes and sometimes scattered 1-1.2 mm patent glandular trichomes. Stipules lanceolate, distinct. Leaves 1(or 2) alternate but opposite at inflorescence; petiole with 0.3-0.6 mm retrorse ± appressed nonglandular trichomes; leaf blade 3.4-7.2 cm, palmately cleft, ratio of main sinus/middle segment length = 0.78-0.82, pilose with appressed nonglandular trichomes and rarely ± patent glandular trichomes; segments 5, rhombic, 7.3-9.4 mm wide at base, 7-13-lobed in distal half, ratio of second sinus/middle segment length = 0.18-0.27. Cymules solitary, 2-flowered; peduncle 6-11.9 cm. Pedicel 2.2-3.3 cm, with 0.2-0.6 mm retrorse ± appressed nonglandular trichomes; bracteoles lanceolate. Sepals 6.6-7.8 mm, mucro 1.6-2.5 mm, ratio of mucro/sepal length = 0.22-0.37, outside with 0.1-1.2 mm antrorse to patent nonglandular trichomes, inside glabrous. Petals 1.1-1.6 cm, erect to patent, basal 1/3-1/2 of both surfaces with trichomes, margin basally ciliate, pink to purplish, apex rounded. Staminal filaments pinkish, lanceolate, base slightly dilated, abaxially densely covered with 0.4-0.7 mm trichomes but glabrous toward tip; anthers brownish, 1.6-2 mm. Nectaries 5, hemispheric, abaxially glabrous, apex usually with a tuft of trichomes. Stigma reddish. Fruit 1.8-1.9 cm, erect when immature; mericarps smooth, with a basal callus, with 0.3-0.4 mm ± patent nonglandular trichomes; rostrum 1.1-1.2 cm, with a 1.9-2.2 mm narrowed apex; stigmatic remains 3.6-3.8 mm. Seeds 2.4-2.5 mm. Fl. Jun-Aug, fr. Sep-Oct.

● Forests, scrub, meadows; 700-3000 m. Chongqing, Guizhou, W Hubei, N Yunnan.

This seems to be an isolated species with no obvious resemblance to other Geranium species in China. Geranium franchetii is well characterized by its cauline alternate leaves, distinct stipules, and short rootstock, along which are thickened roots. The nectary indumentum is variable. Among the studied specimens no material with glandular trichomes was observed.