Rehder
Description
Clematis roylei is a Himalayan climber of the buttercup family, with about 66 GBIF occurrences recorded from India and Nepal. It is a plant of moist temperate forest and the shrubby ecotones between forest and open slope, scrambling over shrubs, herbaceous vegetation and embankments in cool, humid montane settings. The material photographed at Churta-Khola in West Nepal at about 3200 m in June was recorded at the start of the monsoon, when the temperate forest zone is flushed with new growth and these herbaceous climbers come into flower. The species occupies a broadly montane band along the central and western Himalaya.
It is a slender, somewhat woody-based herbaceous to subscandent climber whose petioles and rachises twine to provide support, the leaves being opposite and compound, typically pinnate to ternate with toothed or lobed, acuminate leaflets. The nodding, campanulate flowers lack true petals; the floral envelope consists of four (occasionally more) connivent sepals that are commonly bluish, purple, violet or dull yellow and frequently softly hairy on the margins and outer surface. The numerous stamens surround a cluster of carpels which, in fruit, develop into the characteristic achenes each tipped by a long, persistent, plumose feathery style that aids wind dispersal.
Clematis is a large, cosmopolitan genus, and roylei belongs to the nodding-flowered Himalayan assemblage allied to the C. connata group, with which it has often been associated taxonomically. These climbers contribute to the structural complexity of forest margins and provide nectar to montane pollinators. The species is locally distributed but not formally evaluated; its persistence is tied to the maintenance of intact mid-montane forest and shrubland habitats.
Author: Rehder · Sources: POWO (Kew), GBIF, Flora of Nepal, Hooker Flora of British India, Annotated Checklist of the Flowering Plants of Nepal, Tamura Ranunculaceae