1410

ARBORETUM AND FRUTICETUM.

PART III.

leaves borne on a shoot that is developed in the same year with themselves.Petiole of leaf not obvious; disk of leaf elliptical, unequal at the base,dentate. Indigenous to the west of Asia, and upon the shores of the CaspianSea; and to Imiretta and Georgia, on the south of Mount Caucasus. ( N. DuHam.) Introduced in 1760; flowering in April or May; and growing tothe height of from 50 ft. to 70 ft.

Description, §c. The zelkoua, in its native country, according to Michaux,is a tree of the largest size, growing to the height of from 75 ft. to 80 ft., witha trunk of the diameter of about 4 ft. The trunk is straight and upright, oftenattaining the height of 25 ft. or 30 ft. before itthrows out a single branch. The base of thetrunk is not enlarged, like that of most othertrees, its thickness being very little greater atthe surface of the ground than it is at the pointof ramification. Like that of the hornbeam, itis marked with longitudinal furrows, like opengutters. The head is large, tufted, and verymuch branched; but the branches, thoughwidely extended, are more slender, and morevertical in their direction, than is generally thecase with forest trees. The bark of the trunk isnot grey and cracked, like that of the elm orthe oak, but resembles rather that of the horn-beam or beech. As is the case with those trees,the surface of the bark of the zelkoua is smooth,and its texture is firm and compact; but it hasthis remarkable difference, that, when the treebecomes about 8 in. in diameter, it scales off'in large thin pieces. The flowers are small, ofa greenish brown, and smell like those of the elder; and they are disposed ingroups along the shoots of the current year. The fruit is not larger than apea; and the seeds, which are contained in little gibbous capsules, having twocells, are about the size of a grain of hemp-seed. In Imiretta (a pastoraldistrict lying between Georgia and the shores of the Black Sea), where thezelkoua is found in the greatest abundance, the seeds ripen in the month ofOctober; but in France they always drop off before they have completedtheir maturity. This is the more remarkable, from the tree having beenintroduced into France above seventy years ago, and there being at Versaillesa tree above fifty years old, in a most vigorous state of growth, which hasresisted the most severe frosts. The foliage strongly resembles that of theelm in its general appearance. The leaves are borne on very short petioles,and are generally from 1 in. to 3 in. long. They are alternate, and equallydentated, or rather crenulated; differing, in this respect, from those of everykind of elm known; the leaves of the elm always having every large indentationaccompanied by a smaller one. The leaves of the zelkoua are, also, of a muchfirmer and drier texture than those of the elm; and, it is said, are not, like thoseof the latter tree, liable to the attacks of insects. When the first tree of thisspecies planted in France was cut down, in 1820, it was found to be 70 ft.in height, and its trunk to be 7 ft. in circumference at 5 ft. from the ground.The bole of the trunk was 20 ft. in length, and of nearly uniform thickness;and the proportion of heart-wood to the sap-wood was about three quartersof its diameter. This tree was about fifty years old, but was still in a growingstate, and in vigorous health. (See Michaux’s Memoire sur le Zelkoua, Paris,1831.) Descemet, in his Tableau Historique des Progres dela Culture des Arbresa Odessa, &c., describes this species as a “lofty and beautiful tree, a nativeofMingrelia and Caucasus, which is distinguished by its shining green, broadlycrenulated leaves, and its smooth and greenish trunk.” (p. 60.) In Britishgardens, the rate of growth of this tree is similar to that of the beech orcommon hornbeam ; it attaining the height of 20 ft. in 10 years.