10. THUJA L. Arbor-vitæ.
Resinous aromatic trees, with thin scaly bark, soft durable straight-grained heartwood, thin nearly white sapwood, slender spreading or erect branches, pyramidal heads, flattened lateral pendulous branchlets disposed in one horizontal plane, forming a flat frond-like spray and often finally deciduous, and naked buds. Leaves decussate, scale-like, acute, stomatiferous on the back, on leading shoots appressed or spreading, rounded or slightly keeled on the back, narrowed into long slender points, on lateral branchlets much compressed in the lateral ranks, prominently keeled and nearly covering those of the other ranks; on seedling plants linear-lanceolate, acuminate, spreading or reflexed. Flowers minute, monœcious, from buds formed the previous autumn, terminal, solitary, the two sexes usually on different branchlets; male ovoid, with 4—6 decussate filaments, enlarged into suborbicular peltate connectives bearing on their inner face 2—4 subglobose anther-cells; female oblong, with 8—12 oblong acute scales opposite in pairs, the ovuliferous scales at their base bearing usually 2 erect bottle-shaped ovules. Fruit an ovoid-oblong erect pale cinnamon-brown cone maturing in one season, its scales thin (thick in one species), leathery, oblong, acute, marked near the apex by the thickened free border of the enlarged flower-scales, those of the 2 or 3 middle ranks largest and fertile. Seeds usually 2, erect on the base of the scale, ovoid, acute, compressed, light chestnut-brown; seed-coat membranaceous, produced except in one species into broad lateral wings distinct at the apex; cotyledons 2, longer than the superior radicle.
Thuja is confined to northeastern and northwestern America, to Japan, Korea and northern China. Five species are recognized. Of the exotic species the Chinese Thuja orientalis, L., with many varieties produced by cultivation, is frequently planted in the United States, especially in the south and west, for the decoration of gardens, and is distinguished from the other species by the thick umbonate scales of the cone, only the 4 lower scales being fertile, and by the thick rounded dark red-purple seeds without wings.
Thuja is the classical name of some coniferous tree.
CONSPECTUS OF THE NORTH AMERICAN SPECIES.
Fruit with usually 4 fertile scales.1. [T. occidentalis] (A). Fruit with usually 6 fertile scales.2. [T. plicata] (B, F, G).
1. [Thuja occidentalis] L. White Cedar. Arbor-vitæ.
Leaves on leading shoots often nearly ¼′ long, long-pointed and usually conspicuously glandular, on lateral branchlets much flattened, rounded and apiculate at apex, without glands or obscurely glandular-pitted, about ⅛′ long. Flowers opening in April and May, liver color. Fruit ripening and discharging its seeds in the early autumn, ⅓′—½′ long; seeds ⅛′ long, the thin wings as wide as the body.
A tree, 50°—60° high, with a short often lobed and buttressed trunk, occasionally 6° although usually not more than 2°—3° in diameter, often divided into 2 or 3 stout secondary stems, short horizontal branches soon turning upward and forming a narrow compact pyramidal head, light yellow-green branchlets paler on the lower surface than on the upper, changing with the death of the leaves during their second season to light cinnamon-red, growing darker the following year, gradually becoming terete and abruptly enlarged at the base and finally covered with smooth lustrous dark orange-brown bark, and marked by conspicuous scars left by the falling of the short pendulous lateral branchlets. Bark ¼′—⅓′ thick, light red-brown often tinged with orange color and broken by shallow fissures into narrow flat connected ridges separating into elongated more or less persistent scales. Wood light, soft, brittle, very coarse-grained, durable, fragrant, pale yellow-brown; largely used in Canada and the northern states for fence-posts, rails, railway-ties, and shingles. Fluid extracts and tinctures made from the young branchlets are sometimes used in medicine.
Distribution. Frequently forming nearly impenetrable forests on swampy ground or often occupying the rocky banks of streams, from Nova Scotia and New Brunswick, northwestward to the mouth of the Saskatchewan, and southward through eastern Canada to southern New Hampshire, central Massachusetts, New York, central Ohio, northern Indiana and Illinois, and Minnesota; occasionally on the high mountains of Virginia, West Virginia, and northeastern Tennessee, and on the mountains of western Burke County, North Carolina, at an altitude of 3000 feet; very common at the north, less abundant and of smaller size southward.
Often cultivated, with many, often dwarf, forms produced in nurseries, as an ornamental tree and for hedges; and in Europe from the middle of the sixteenth century.
2. [Thuja plicata] D. Don. Red Cedar. Canoe Cedar.
Leaves on leading shoots ovate, long-pointed, often conspicuously glandular on the back, frequently ¼′ long, on lateral branchlets ovate, apiculate, without glands or obscurely glandular-pitted, usually not more than ⅛′ long, mostly persistent 2—5 years. Flowers about 1/12′ long, dark brown. Fruit ripening early in the autumn, clustered near the ends of the branches, much reflexed, ½′ long, with thin leathery scales, conspicuously marked near the apex by the free border of the flower-scale furnished with short stout erect or recurved dark mucros; seeds often 3 under each fertile scale, rather shorter than their usually slightly unequal wings about ¼′ long.
A tree, frequently 200° high, with a broad gradually tapering buttressed base sometimes 15° in diameter at the ground and in old age often separating toward the summit into 2 or 3 erect divisions, short horizontal branches, usually pendulous at the ends, forming a dense narrow pyramidal head, and slender much compressed branchlets often slightly zigzag, light bright yellow-green during their first year, then cinnamon-brown, and after the falling of the leaves, lustrous and dark reddish brown often tinged with purple, the lateral branchlets 5′—6′ long, light green and lustrous on the upper surface, somewhat paler on the lower surface, turning yellow and falling generally at the end of their second season. Bark bright cinnamon-red, ½′—¾′ thick, irregularly divided by narrow shallow fissures into broad ridges rounded on the back and broken on the surface into long narrow rather loose plate-like scales. Wood light, soft, not strong, brittle, coarse-grained, easily split, dull brown tinged with red; largely used in Washington and Oregon for the interior finish of buildings, doors, sashes, fences, shingles, and in cabinet-making and cooperage. From this tree the Indians of the northwest coast split the planks used in the construction of their lodges, carved the totems which decorate their villages, and hollowed out their great war canoes, and from the fibres of the inner bark made ropes, blankets, and thatch for their cabins.
Distribution. Singly and in small groves on low moist bottom-lands or near the banks of mountain streams, from the sea-level to elevations of 6000° in the interior, from Baranoff Island, Alaska, southward along the coast ranges of British Columbia, western Washington, and Oregon, where it is the most abundant and grows to its largest size, and through the California-coast region to Mendocino County, ranging eastward along many of the interior ranges of British Columbia, northern Washington, Idaho, and Montana to the western slope of the continental divide.
Often cultivated as an ornamental tree in the parks and gardens of western and central Europe where it has grown rapidly and vigorously, and occasionally in the middle and north Atlantic states.