Қарағайша жалбыр (Ulmus glabra) сипаттамасы

Species of flowering plant in the elm family Ulmaceae

Ulmus glabra Hudson, the wych elm or Scots elm, has the widest range of the European elm species, from Ireland eastwards to the Ural Mountains, and from the Arctic Circle south to the mountains of the Peloponnese and Sicily, where the species reaches its southern limit in Europe; it is also found in Iran. A large deciduous tree, it is essentially a montane species, growing at elevations up to , preferring sites with moist soils and high humidity. The tree can form pure forests in Scandinavia and occurs as far north as latitude 67°N at Beiarn in Norway. It has been successfully introduced as far north as Tromsø and Alta in northern Norway (70°N). It has also been successfully introduced to Narsarsuaq, near the southern tip of Greenland (61°N). The tree was by far the most common elm in the north and west of the British Isles and is now acknowledged as the only indisputably British native elm species. Owing to its former abundance in Scotland, the tree is occasionally known as the Scotch or Scots elm; Loch Lomond is said to be a corruption of the Gaelic Lac Leaman interpreted by some as 'Lake of the Elms', 'leaman' being the plural form of leam or lem, 'elm'. Closely related species, such as Bergmann's elm U. bergmanniana and Manchurian elm U. laciniata, native to northeast Asia, were once sometimes included in U. glabra; another close relative is the Himalayan or Kashmir elm U. wallichiana. Conversely, Ulmus elliptica from the Caucasus, considered a species by some authorities, is often listed as a regional form of Ulmus glabra.

The word "wych" (also spelled "witch") comes from the Old English wice, meaning pliant or supple, which also gives definition to wicker and weak. Jacob George Strutt's 1822 book, Sylva Britannica attests that the Wych Elm was sometimes referred to as the "Wych Hazel", a name now applied to the unrelated species Hamamelis, commonly called “wych hazels”.

The type sometimes reaches heights of , typically with a broad crown where open grown, supported by a short bole up to diameter at breast height (DBH). Normally, root suckers are not seen; natural reproduction is by seed alone. The tree is notable for its very tough, supple young shoots, which are always without the corky ridges or 'wings' characteristic of many elms. The alternate leaves are deciduous, 6–17 cm long by 3–12 cm broad, usually obovate with an asymmetric base, the lobe often completely covering the short (<5 mm) petiole; the upper surface is rough. Leaves on juvenile or shade grown shoots sometimes have three or more lobes near the apex. The perfect hermaphrodite flowers appear before the leaves in early spring, produced in clusters of 10–20; they are 4 mm across on 10 mm long stems, and being wind pollinated, are apetalous. The fruit is a winged samara 20 mm long and 15 mm broad, with a single, round, 6 mm seed in the centre, maturing in late spring.

While the species is highly susceptible to Dutch elm disease, it is less favoured as a host by the elm bark beetles, which act as vectors. Research in Spain has indicated the presence of a triterpene, alnulin, rendering the tree bark less attractive to the beetle than the field elm, though at 87 μg/g dried bark, its concentration is not as effective as in Ulmus laevis (200 μg/g). Moreover, once the tree is dying, its bark is quickly colonized by the fungus Phoma, which radically reduces the amount of bark available for the beetle to breed on. In European trials, clones of apparently resistant trees were inoculated with the pathogen, causing 85 – 100% wilting, resulting in 68% mortality by the following year. DNA analysis by Cemagref (now Irstea) in France has determined the genetic diversity within the species is very limited, making the chances of a resistant tree evolving rather remote. Still, a 300 year old example growing in Grenzhammer, Ilmenau has been scientifically proven to be resistant to Dutch elm disease. The Swedish Forest Tree Breeding Association at Källstorp produced triploid and tetraploid forms of the tree, but these proved no more resistant to Dutch elm disease than the normal diploid form. In trials conducted in Italy, the tree was found to have a slight to moderate susceptibility to elm yellows, and a high susceptibility to the elm leaf beetle Xanthogaleruca luteola.

Wych elm wood is prized by craftsmen for its colouring, its striking grain, its 'partridge breast' or 'catspaw' markings, and when worked, its occasional iridescent greenish sheen or 'bloom'. The bosses on old trees produce the characteristic fissures and markings of 'burr elm' wood. Bosses fringed with shoots are burrs, whereas unfringed bosses are burls.

U. glabra hybridises naturally with U. minor, producing elms of the Ulmus × hollandica group, from which have arisen a number of cultivars:

However, hybrids of U. glabra and U. pumila, the Siberian elm, have not been observed in the field and only achieved in the laboratory, though the ranges of the two species, the latter introduced by man, overlap in parts of Southern Europe, notably Spain. The earlier trees were raised in response to the initial Dutch elm disease pandemic that afflicted Europe after the First World War, and were to prove vulnerable to the much more virulent strain of the disease that arrived in the late 1960s. However, further research eventually produced several trees effectively immune to disease, which were released after 1989. Arno, Clusius, Columella, Commelin, Den Haag, Dodoens, Groeneveld, Homestead, Lobel, Nanguen = , Pioneer, Plinio, Regal, San Zanobi, Urban, Wanoux = .