Clematis rehderiana Craib

Vines woody. Branches shallowly 5--8-grooved, sparsely puberulous. Leaves usually 2-pinnate, sometimes 1-pinnate; petiole 2.8--6 cm; leaflet blades ovate to pentagonal-ovate, (2--)3.5--7 × (1.6--)3--5.8 cm, papery, 3-lobed or parted, both surfaces appressed sericeous-puberulous, base cordate, truncate, or broadly cuneate, margin dentate, apex acuminate to caudate-acuminate; basal veins abaxially ± prominent. Cymes axillary, 4- to many flowered, often paniclelike; peduncle 7--13 cm; bracts ovate to rhombic, 0.5--3.5 cm, often 3-lobed. Flowers 1.4--1.8 cm in diam. Pedicel 0.3--2.8 cm, densely puberulous. Sepals 4, yellowish, erect, oblong to narrowly oblong, 1.4--1.9 × 0.5--0.7 cm, abaxially densely appressed sericeous-puberulous, adaxially glabrous or sparsely puberulous, margin abaxially velutinous, apex ± acute and recurved. Stamens 1--1.3 cm; filaments pubescent; anthers narrowly oblong to oblong, 1.8--3 mm, glabrous or only abaxially puberulous on connective, apex obtuse. Ovaries puberulous. Style 1--1.3 cm, densely villous. Achenes ovate to suborbicular, 3--4 × 2.5--3 mm, puberulous; persistent style 2--2.5 cm, plumose. Fl. Jul--Aug, fr. Sep.

Nepal, S.E. Tibet, S. W. China.

E Qinghai, W Sichuan, Xizang, NW Yunnan [Nepal].

2700-3000 m

Slopes, scrub, along streams; 2000--2500 m.

Clematis nutans Royle var. thyrsoidea Rehder & E. H. Wilson; C. veitchiana Craib.

Flowering from July to August; fruiting in September.

Clematis rehderiana is close relative of Clematis aethusifolia, but differs from the latter in its leaflet blades lobed (vs. parted), cymes usually many flowered (vs. few flowered), paniclelike.

Clematis rehderiana is occurring in E Qinghai, W Sichuan, Xizang, NW Yunnan of China, Nepal.

Phylogenetic relationships within Clematis, including Naravelia, Archiclematis and Clematopsis, were analysed using nucleotide sequences of chloroplast DNA sequences matK and trnK introns, atpB-rbcL spacer, rpoB-trnC spacer, psbA-trnH-trnQ spacer, rbcL-accD spacer and the nuclear ITS regions (Miikeda et al., 2006). The phylogenetic trees resulting from these analyses suggested nine major clades. The genera Archiclematis, Naravelia and Clematopsis were found to be nested within the genus Clematis, and should be included within it. Within the genus Clematis, the traditional subgenus Viorna was found to be monophyletic. The remaining subgenera (Flammula, Clematis and Campanella) and sections Flammula, Clematis and Cheiropsis, however, were found to be paraphyletic or polyphyletic. Enormous morphological diversification and very few nucleotide substitutions within Clematis indicate the recent radiation of the genus.

Vines woody. Branches shallowly 5-8-grooved, sparsely puberulous. Leaves usually 2-pinnate, sometimes 1-pinnate; petiole 2.8-6 cm; leaflet blades ovate to pentagonal-ovate, 3.5-7 cm long, 3-5.8 cm wide, papery, 3-lobed or parted, both surfaces appressed sericeous-puberulous, base cordate, truncate, or broadly cuneate, margin dentate, apex acuminate to caudate-acuminate; basal veins abaxially ± prominent. Cymes axillary, 4- to many flowered, often paniclelike; peduncle 7-13 cm; bracts ovate to rhombic, 0.5-3.5 cm, often 3-lobed. Flowers 1.4-1.8 cm in diameter. Pedicel 0.3-2.8 cm, densely puberulous. Sepals 4, yellowish, erect, oblong to narrowly oblong, 1.4-1.9 cm long, 0.5-0.7 cm wide, abaxially densely appressed sericeous-puberulous, adaxially glabrous or sparsely puberulous, margin abaxially velutinous, apex ± acute and recurved. Stamens 1-1.3 cm; filaments pubescent; anthers narrowly oblong to oblong, 1.8-3 mm, glabrous or only abaxially puberulous on connective, apex obtuse. Ovaries puberulous. Style 1-1.3 cm, densely villous. Achenes ovate to suborbicular, 3-4 mm long, 2.5-3 mm wide, puberulous; persistent style 2-2.5 cm, plumose.

Growing in slopes, scrub, along streams; 2000-2500 m.

Clematis rehderiana is a species of Clematis native to Nepal and China (Qinghai and Tibet). It has gained the Royal Horticultural Society's Award of Garden Merit.