(C.E.C.Fisch.) Grey-Wilson
Description
Clematis tibetana var. vernayi is a Himalayan and Tibetan climber recorded principally from China and Nepal among its roughly 289 occurrences, the records from New Zealand, the Netherlands, the United States and Canada reflecting its popularity in horticulture rather than a natural range, since this is the celebrated nodding yellow-flowered clematis widely cultivated in temperate gardens. In the wild it inhabits open subalpine and alpine slopes, scrub, rocky banks and dry valley sides, often scrambling over shrubs and boulders in well-drained, sunny situations. The photographed plant from the Bauli-Khola in West Nepal, at about 3500 m and flowering in July, is typical of its high-montane occurrence in the inner, drier Himalayan valleys.
It is a woody-based, semi-scandent perennial climbing by twining petioles, with deeply divided, pinnately compound leaves whose narrow leaflets are often lobed, toothed and somewhat glaucous, an adaptation to the dry, exposed habitat. The flowers are solitary, nodding and broadly campanulate to lantern-shaped, lacking true petals; the showy structures are four thick, leathery sepals coloured deep yellow, frequently flushed purple-brown outside, surrounding numerous stamens. The fruit is a head of achenes each bearing a long, conspicuously plumose persistent style, forming the silvery feathery seed-heads characteristic of the genus and aiding wind dispersal.
Clematis section Meclatis, the yellow-flowered Asian group to which this taxon belongs, has been studied in detail by Grey-Wilson, who recombined the variety; the thick-sepalled, glaucous, dry-habitat forms of the C. tibetana complex have long been valued by gardeners as the orange-peel clematis for their unusually substantial sepals. Ecologically the plumed achenes exploit wind for dispersal across open terrain. Widespread in the wild and abundant in cultivation, the variety is of no conservation concern, and its garden derivatives remain among the most familiar Himalayan contributions to ornamental horticulture.
Author: (C.E.C.Fisch.) Grey-Wilson · Sources: POWO (Kew), GBIF, Flora of China, Annotated Checklist of the Flowering Plants of Nepal, Grey-Wilson's monograph Clematis the Genus