Clematis potaninii Maxim.

Vines woody. Branches shallowly 5- or 6-grooved, appressed puberulous. Leaves usually (1 or)2-pinnate; petiole 3--5 cm; leaflet blades ovate to broadly ovate, 1.5--6 × 0.8--5.5 cm, thin papery, both surfaces sparsely appressed puberulous, base broadly cuneate, rounded, or subcordate, margin serrate, apex acute to acuminate; basal veins flat. Cymes arising from axils of leaves on current year’s branches, 1--3(or 4)-flowered; peduncle 5.5--15 cm; bracts ternate or simple, 3-lobed. Flowers 3--7 cm in diam. Pedicel 3--9.8 cm, appressed puberulous. Sepals 5 or 6(or 7), white, cuneate-obovate to narrowly obovate, 1.8--3.8 × 0.8--2.4 cm, abaxially densely appressed puberulous, adaxially glabrous, apex rounded and apiculate. Stamens 0.7--1.8 cm, glabrous; anthers narrowly oblong, 2--3 mm, apex obtuse. Ovaries pubescent. Style 7--11 mm, densely villous. Achenes obovate to elliptic, 3--4.5 × 2--2.8 mm, glabrous; persistent style 2.5--3.2 cm, plumose. Fl. Jun--Aug, fr. Aug--Oct.

S Gansu, S Shaanxi, N to W Sichuan, E Xizang, NW Yunnan.

* Forests, forest margins, slopes; 1400--4000 m.

Clematis fargesii Franchet; C. fargesii var. souliei Franchet ex Finet & Gagnepain; C. montana Buchanan-Hamilton ex de Candolle var. potaninii (Maximowicz) Finet & Gagnepain; C. potaninii var. fargesii (Franchet) Handel-Mazzetti.

Clematis potaninii, the old man's beard, is a species of flowering plant in the family Ranunculaceae, native to Tibet and central China. A deciduous woody vine, in the wild it is found climbing on slopes and in forests, particularly forest edges, at elevations from 1,400 to 4,000 m (4,600 to 13,100 ft). Its cultivar 'Summer Snow', also known as 'Paul Farges', has gained the Royal Horticultural Society's Award of Garden Merit.

Seedhead