A deciduous climber, growing 10 to 20 ft high; young stems ribbed and not downy. Leaves 6 to 8 in. long, pinnately divided, the primary divisions usually trifoliolate; leaflets with slender stalks 1 to 2 in. long, dull glaucous green, ovate or lanceolate, 1⁄2 to 21⁄2 in. long, usually angularly toothed or deeply lobed, but sometimes entire, quite glabrous. Flowers yellow, slightly fragrant, 11⁄2 to 2 in. across, produced during August and September singly on slender stalks 2 to 4 in. long (lengthening in fruit); sepals ovate, pointed, downy on the inside. Seed-vessel with slender, feathered styles 11⁄2 in. long, the whole forming a handsome globular tuft over 3 in. across.
In a wild state this clematis extends from the Caucasus and Persia to the Himalaya, N. China, and Manchuria; it accordingly varies considerably in minor points. The plant usually known as C. graveolens is a less glaucous form, the leaves slightly downy, the leaflets mostly larger. C. orientalis was introduced in 1731.
C. glauca Willd. var. akebioides (Maxim.) Rehd. & Wils. C. orientalis var. akebioides Maxim. – This has flowers 11⁄2 to 13⁄4 in. diameter, deep orange yellow. A handsome Chinese form introduced for Messrs Veitch by Wilson, which flowers late into October, and is more vigorous than the type. It differs from C. orientalis in having the sepals downy on the margins only.
A remarkable clematis of the orientalis alliance was introduced by Ludlow, Sherriff, and Elliott from the Himalaya in 1947, under LSE 13342, with thick, fleshy sepals that have been likened to orange-peel. It was given an Award of Merit when shown by Messrs Ingwersen in 1951.
From the Supplement (Vol. V)
C. orientalis, described by Linnaeus in 1753, is the senior member of a taxonomically difficult complex of species with a wide range in Eurasia, most of which have been placed under it as varieties or even confused with it. The group has been elucidated by Dr Christopher Grey-Wilson of the Kew Herbarium in The Plantsman, Vol. 7 (4), pp. 193-204 (1986).
The leading characters of C. orientalis in the modern, restricted sense, are: leaves pinnate, the leaflets of fleshy texture, mostly three-lobed, commonly untoothed, glaucous. Flowers usually arranged normally many together, in the form of a panicle in which the branches bear the flowers in sets of three. Sepals dull yellowish or greenish yellow, lanceolate to elliptic, acute, up to about 3⁄4 in. long, soon reflexed, hairy at least on the inner surface and at the edge. As in all members of the group, the filaments of the stamens are flattened, with a widened, hairy base, and the styles are hairy, lengthening in fruit.
C. orientalis is of wide distribution, from the eastern Aegean to central Asia and west Pakistan. Although introduced to Britain in the 18th century, it has never been much grown in gardens nor does it deserve to be.
The clematis described under the name C. orientalis in the main work and in previous editions is not the true species. It had been grown at Kew under that name since the late 19th century, but almost certainly it was C. intricata Bunge, for which see in this supplement under C. akebioides.
C. graveolens Lindl. C. orientalis auct., in part, not L.; C. orientalis subsp. graveolens (Lindl.) Kuntze – This species has in the past often been treated as synonymous with C. orientalis, but is certainly distinct. It has more elaborately divided leaves, the primary divisions being themselves pinnate or trifoliolate. The flowers are solitary or up to five in reduced cymose panicles. The sepals are pale yellow, obtuse and notched at the apex, up to almost 1 in. long, spreading but not reflexed, hairy on the outside and at the edge. Described in 1847 from a cultivated plant, it ranges from Afghanistan to Nepal.
Having a fairly large, flat-faced flower, this could be a quite valuable ornamental, though it is scarcely known today, and it might also be of use in breeding. The specific epithet refers to the heavy, not altogether pleasant odour of the flowers.
For C. glauca var. akebioides and the Ludlow and Sherriff introduction, mentioned on page 655, see C. akebioides and C. tibetica in this supplement.