A species closely allied to, or perhaps a variety of, C. orientalis, growing 10 to 15 ft high; stems slightly downy. Leaves grey-green, like those of C. orientalis, but downy when young; leaflets raggedly toothed, and sometimes two- or three-lobed. Flowers rich yellow, solitary on downy stalks 3 to 6 in. long; sepals nearly 2 in. long, narrowly ovate, long and slenderly pointed, downy outside and at the edges. Seed-vessels crowned with long feathered styles. Bot. Mag., t. 7710.
Native of Central Asia; introduced to Kew from St Petersburg in 1898. It was introduced again in 1911 from W. Kansu by Purdom; this form was raised at Wisley and seed from the plants there widely distributed from 1919 onward. It is the handsomest yellow-flowered clematis in cultivation, the finest flowers being about 4 in. across. It differs from C. orientalis in the larger flowers, downy stems, flower-stalks, etc. It is a superior autumnal flowering plant.
var. obtusiuscula Rehd. & Wils. – From the typical C. tangutica this variety is distinguished by its more woolly young shoots, leaf-stalks, and flower-stalks; by its smaller, more sparsely toothed leaflets; and by the shorter, blunt or scarcely pointed sepals 1 to 11⁄4 in. long. (In the typical tangutica the sepals have long slender points and are of greater length.) The flowers are rich yellow and solitary on stalks 3 to 4 in. long.
Native of W. Szechwan, China, at altitudes of 8,000 to 10,000 ft; introduced by Wilson in 1908. On the whole it is scarcely so handsome a plant as the type, although it possibly flowers more freely and grows more vigorously.
From the Supplement (Vol. V)
In the last two sentences of the second paragraph (page 660), Mr Bean meant by C. orientalis some clematis grown under that name at Kew in his time (possibly C. intricata).
var. obtusiuscula – Another point of difference between this variety and the typical state is that the sepals are more spreading. Dr Grey-Wilson remarks that none of the live plants he has seen under the name is true. To this it may be added that the type-locality for var. obtusiuscula is the Tapao-shan in western Szechwan, north-east of Kangding (Tatsien-lu). However, some at least of the seedlings distributed by the Royal Horticultural Society under this name were raised from seed collected in Kansu, and the plant that received an Award of Merit when shown by (Sir) Frederick Stern in 1913 was also from this area, raised from seeds collected by his friend George Fenwick-Owen near ‘Chone’ – probably Choni.
C. ‘Aureolin’. – A seedling of C. tangutica backcrossed to a hybrid of that species, raised at the Boskoop Experimental Station. It is vigorous, with large flowers borne over a long period in late summer and early autumn (Dendroflora, No. 15/16, p. 60 (fig.) and p. 62 (1979)).
C. ‘Bill Mackenzie’. – This hybrid, of uncertain parentage, was raised by Valerie Finnis (Lady Scott) at the Waterperry Horticultural School near Oxford, a few years before 1969. It is usually assumed to be a seedling of the Ludlow and Sherriff ‘Orange Peel’ clematis (see under C. tibetana in this supplement), but Dr Grey-Wilson suggests C. tangutica crossed with its var. obtusiuscula. It is at any rate a fine, very vigorous clematis with widely opening, lemon-yellow flowers, borne abundantly over a long period. Unfortunately some other, inferior, seedlings from the original batch were distributed under the same name. The true clone grows in the Royal Botanic Garden, Edinburgh, and is portrayed in The Garden (Journ. R.H.S.), Vol. 108, p. 327 (1983).
C. ‘Corry’. – This is the result of a deliberate cross between C. tangutica and C. tibetana subsp. vernayi (“Orange Peel” form), made by the Dutch firm of P. G. Zwijnenburg and put into commerce in 1975. It received a Silver Medal at Boskoop in 1978 and is now available in this country. It is vigorous, with large flowers opening fairly widely. Similar crosses involving these and other members of the C. orientalis alliance have been made at the Boskoop Experimental Station, and two of these, still under number, received Silver Medals at the same time (Dendroflora, No. 15/16, p. 51 (1979)).