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A tree to 60 ft in the Himalaya, but reaching 100 ft in W. China (var. prattii). Bark variable in colour, peeling in horizontal, papery flakes; young shoots densely covered with grey down, becoming reddish brown. Leaves ovate, rounded at the base, pointed, 2 to 31⁄2 in. long, about two-thirds as wide, rather coarsely and irregularly toothed; upper surface dark green, with scattered down; lower surface pale, downy on the midrib and veins, the latter in nine to twelve pairs; leaf-stalk 3⁄4 in. long, downy. Fruiting catkins 11⁄2 in. long, 1⁄3 in. diameter, cylindrical; scales ciliate on the margins, three-lobed, the middle lobe considerably the longer, and round at the end; lateral lobes erect.
Native of the Himalaya and thence eastward and northward into China, where it passes over into the var. prattii Burkill, a rather indistinct variety in which the leaves are more downy beneath, the fruit-scales more ciliate at the margin, with spreading, not erect, lobes. This variety is found in W. Szechwan and Kansu, but the Himalayan type appears to extend as far as Yunnan. B. utilis was introduced from Sikkim in 1849 by Sir Joseph Hooker and from China by Wilson (W. 4035, 4087, and 4089) and by Forrest (F. 15381). The Himalayan provenance is said to be tender, but the Chinese trees have proved hardy enough and it is difficult to believe that all the Himalayan forms are tender.
B. utilis and var. prattii are represented in cultivation by trees 35 to 60 ft high at Westonbirt, Glos.; Hergest Croft, Heref.; Werrington Park, Cornwall; Youngsbury, Ware, Herts.; and Highdown, Sussex. The last-named was collected by George Fen wick-Owen on the frontier between China and Tibet in 1912. In one of the trees at Westonbirt, raised from F. 15381 and planted in 1924, the trunk is of a dark chocolate colour, with bands of purplish grey and mahogany; in another, it is reddish to orange-brown. The origin of the latter is uncertain, but in W. 4087 the bark is usually of that colour. In W. 4089 it is greyish (Coltman Rogers, Journ. R.H.S., Vol. 53, 1928, p. 63). The beautiful specimen at Grayswood Hill, Haslemere, planted in 1882, was certainly raised from Himalayan seed and differs from the Chinese representatives of the species in its creamy-white bark slightly flushed with pink. It measures 40 × 43⁄4 ft (1968); cf. 30 × 2 ft (1906).
specimens: Kew, 46 × 33⁄4 ft (1974); Wakehurst Place, Sussex, 52 × 51⁄4 ft (1981); Grayswood Hill, Haslemere, Surrey, this tree has died; Furzey Gardens, Hants, 52 × 41⁄4 ft (1973); Speech House, Glos., pl. 1952, 58 × 51⁄4 ft (1983); Werrington Park, Cornwall, 46 × 41⁄4 ft (1977); Trewithen, Cornwall, 55 × 5 ft (1985); Hergest Croft, Heref., 46 × 31⁄4 ft (1978); Howick, Northumb., 60 × 41⁄4 ft (1978); Brook House, Co-Londonderry, 50 × 61⁄4 ft (1976).
In an interesting note on B. utilis (Journ. R.H.S., Vol. 99 (1974), pp. 536-9), A. D. Schilling remarks on a long-standing error concerning the locality in Nepal in which Wallich collected the type-specimen of B. utilis during his expedition of 1820-21. According to his label on the specimen, it was collected on the Gossain-than. But this mountain lies in a region of difficult access, far to the north of Kathmandu on the Tibetan side of the frontier. It is virtually certain that Wallich never visited this area, and that the specimen was in fact collected on the Gossain-kund, which lies only three or four days’ journey from Kathmandu. In this area the usual bark-colour is pale amber brown and not creamy white as stated in the original printing of the present edition, at the end of the entry on page 434.
An interesting and stimulating article on B. utilis and its varieties, by K. Ashburner and A. D. Schilling, was published in The Plantsman, Vol. 7(2), pp. 116-25 (1985); a shortened version by the same authors, illustrated by colour photographs, will be found in The Garden (Journ. R.H.S), Vol. 110, pp. 523-5 (1985). This is mentioned further below.
var. jacquemontii (Spach) Winkler B. jacquemontii Spach; B. utilis subsp. jacquemontii (Spach) Kitamura – As suggested on page 434, B. jacquemontii is not sharply demarcated from B. utilis, and a varietal or subspecific rank is preferable. The type-specimen on which Spach founded his species in 1841 had been collected just over a decade earlier by the French traveller Victor Jacquemont in Kumaon, probably in the region of the upper Sutlej river, north-east of Simla, an area from which other specimens, collected by Edgeworth, were considered by Dr Stapf to be intermediate between B. utilis and B. jacquemontii. However, Ashburner and Schilling put the boundary between the brown bark forms (var. utilis) and the white bark forms (var. jacquemontii) in central Nepal, the approximate dividing line being the Kali Gandaki gorge (op. cit., pp. 117-19). The two views are not wholly contradictory, since an almost white bark can be associated with foliage that agrees with typical B. utilis, and the status of such forms is controversial.
Birches that have been included in B. jacquemontii occupy a vast area stretching from Kumaon or perhaps western Nepal at its south-eastern extremity through the north-western Himalaya into the complex mountain systems of inner Kashmir, West Pakistan (Swat Himalaya) into the Hindu Kush of Afghanistan. The extreme north-western state of the aggregate differs markedly from typical B. utilis in having leaves with only five or six more widely spaced pairs of veins (against ten to fourteen), broad-cuneate at the base (against more or less truncate). This race has been distinguished as B. utilis subsp. occidentalis Kitamura (B. jacquemontii subsp. occidentalis (Kitamura) Browicz). Ashburner and Schilling, who give this birch the rank of variety, define it differently, attributing to it: winter-buds conspicuously encrusted with white resin; shoots densely warted and only slightly pubescent; leaves markedly glandular beneath, with seven to ten pairs of veins. They also give it a wider range to the east, as far as Kashmir and Lahul. This birch, however defined, presents taxonomic problems, since it really has little in common with typical B. utilis, except in having the scales of the fruiting catkins with narrow lobes, the two lateral lobes ascending. Dr Browicz, in Flora Iranica, remarks that this birch comes into contact with species of Russian Central Asia which also have scales with ascending lateral lobes but these are classified in the section Albae in the Flora of the Soviet Union, while B. utilis is placed in section Costatae with B. ermanii et al.
The Betula utilis complex is now represented by trees from a remarkably large number of natural-source collections, ranging from Kashmir to China, whence the var. prattii has been reintroduced by Roy Lancaster and by Keith Rushforth. See the list of those in the Kew collection at Wakehurst Place (op. cit., p. 122).
The well-known Grayswood Hill tree mentioned on page 433 was fortunately propagated vegetatively before it died, and the clone has been named ‘Grayswood Ghost’. The tree from S.S. & W. 4382, which grew at Wisley outside Aberconway House, is also dead, but vegetative propagations exist and have been named ‘Sauwala White’ (not to be confused with the tree from the same gathering that grows at Wisley on Weather Hill). The white-barked tree in the Royal Botanic Garden, Edinburgh, mentioned on page 434, has been named ‘Inverleith’. Ashburner and Schilling suggest that it is a hybrid of garden origin between B. utilis var. jacquemontii and possibly B. pubescens. The above cultivar-names were all published by them in the article mentioned.
B. ‘Jermyns’, with a strikingly white bark, is near to B. utilis. The original plants came to Messrs Hillier from a Belgian nursery as B. jacquemontii and were so uniform as to indicate that they had been propagated vegetatively. It has been suggested that they belonged to the ‘Doorenbos clone’, originally raised by the late S. G. A. Doorenbos from seed received in 1933, though whence is uncertain, since he received birch seed from several sources in that year. He propagated the original selection by layering and distributed plants to some Dutch nurseries, from which it may have reached Belgium (Dendroflora, No. 20, pp. 30-31 (1983)). There are four good specimens in the Hillier Arboretum. Their bark is creamy white when freshly exposed, but from a distance they are conspicuously white.
B. bhojpattra var. jacquemontii (Spach) Reg.
B. utilis var. jacquemontii (Spach) Winkler