Tall resinous aromatic trees, with scaly bark, spreading branches, flattened branchlets disposed in one horizontal plane and forming an open 2-ranked spray and often ultimately deciduous, straight-grained durable fragrant wood, and naked buds. Leaves scale-like, in 4 ranks, on leading shoots nearly equally decussate, closely compressed or spreading, dying and becoming woody before falling, on lateral flattened branchlets much compressed, conspicuously keeled, and nearly covering those of the other ranks; on seedling plants linear-lanceolate and spreading. Flowers monœcious, solitary, terminal, the two sexes on different branchlets; male oblong, with 12—16 decussate filaments dilated into broad connectives usually bearing 4 subglobose anther-cells; female oblong, subtended at base by several pairs of leaf-like scales slightly enlarged and persistent under the fruit, composed of 6 acuminate short-pointed scales, those of the upper and middle ranks much larger than those of the lower rank, ovate or oblong, fertile and bearing at the base of a minute accrescent ovuliferous scale 2 erect ovules. Fruit an oblong cone maturing in one season, with subcoriaceous scales marked at the apex by the free thickened mucronulate border of the enlarged flower-scales, those of the lowest pair ovate, thin, reflexed, much shorter than the oblong thicker scales of the second pair widely spreading at maturity; those of the third pair confluent into an erect partition. Seeds in pairs, erect on the base of the scale; seed-coat membranaceous, of 2 layers, produced into thin unequal lateral wings, one narrow, the other broad, oblique, nearly as long as the scale; cotyledons 2, about as long as the superior radicle.
Libocedrus is confined to western North America, western South America, where it is distributed from Chile to Patagonia, New Zealand, New Caledonia, New Guinea, Formosa, and southwestern China. Eight species are distinguished.
Libocedrus, from λιβάς and Cedrus, relates to the resinous character of these trees.
1. [Libocedrus decurrens] Torr. Incense Cedar.
Leaves oblong-obovate, decurrent and closely adnate on the branchlets except at the callous apex, ⅛′ long on the ultimate lateral branchlets to nearly ½′ long on leading shoots, those of the lateral ranks gradually narrowed and acuminate at apex, keeled and glandular on the back, and nearly covering the flattened obscurely glandular-pitted and abruptly pointed leaves of the inner ranks. Flowers appearing in January on the ends of short lateral branchlets of the previous year; male tingeing the tree with gold during the winter and early spring, ovate, nearly ¼′ long, with nearly orbicular or broadly ovate connectives, rounded, acute or acuminate at the apex and slightly erose on the margins; female subtended by 2—6 pairs of leaf-like scales, with ovate acute light yellow-green slightly spreading scales. Fruit ripening and discharging its seeds in the autumn, oblong, ¾′—1′ long, pendulous, light red-brown; seeds oblong-lanceolate, ⅓′—½′ long, semiterete and marked below by a conspicuous pale basal hilum; inner layer of the seed-coat penetrated by elongated resin-chambers, filled with red liquid balsamic resin.
A tree, usually 80°—100° or rarely 150° high, with a tall straight slightly and irregularly lobed trunk tapering from a broad base, 3° or 4° or occasionally 6° or 7° in diameter, slender branches erect at the top of the tree, below sweeping downward in bold curves, forming a narrow open feathery crown becoming in old age irregular in outline by the greater development of a few ultimately upright branches forming secondary stems, and stout branchlets somewhat flattened and light yellow-green at first, turning light red-brown during the summer and ultimately brown more or less tinged with purple, the lateral branchlets much flattened, 4′—6′ long, and usually deciduous at the end of the second or third season. Bark ½′—1′ thick, bright cinnamon-red, and broken into irregular ridges covered with closely appressed plate-like scales. Wood light, soft, close-grained very durable in contact with the soil, light reddish brown, with thin nearly white sapwood; often injured by dry rot but largely used for fencing, laths and shingles, the interior finish of buildings, for furniture, and in the construction of flumes.
Distribution. Singly or in small groves from the southeastern slope of Mt. Hood, Oregon, and southward along the Cascade Mountains; on the high mountains of northern California, on the western slopes of the Sierra Nevada, and in Alpine County on their eastern slope, on the Washoe Mountains, western Nevada, in the California coast ranges from the Santa Lucia Mountains, Monterey County to the high mountains in the southern part of the state; on the Sierra del Pinal and the San Pedro Mártir Mountains, Lower California; most abundant and of its largest size on the Sierra Nevada, of central California at elevations of 5000°—7000° above the sea.
Often cultivated as an ornamental tree in western and central Europe, where it grows rapidly and promises to attain a large size; hardy and occasionally planted in the New England and middle Atlantic states.