I. THE WHITE OAK GROUP Acorns annual; leaf lobes rounded; bark usually pale.
KeY TO SPECIES A. Pacific coast species. Deciduous.
B. Foliage blue with silvery lining. (Q. Douglasii) BLUE OAK BB. Foliage green.
C. Acorns slenderly conical; branchlets slender, pendu lous; leaves white lined.
(Q. lobata) CALIFORNIA WHITE OAK CC. Acorns oval; branchlets stout, erect; leaves not white lined. (Q. Garryana) PACIFIC POST OAK AA. Eastern species.
B. Foliage evergreen. (Q. Virginian) LIVE OAK BB. Foliage semi-persistent, blue. (Q. breviloba) DURAND OAK BbB. Foliage deciduous.
C. Leaves pinnately lobed by deep sinuses.
D. Under sides of leaves smooth. (Q. alba) WHITE OAK DD. Under sides of leaves downy.
E. Branches corky; acorn large, in fringed cup.
(Q. macrocarpa) BUR OAK EE. Branches not corky; acorn medium in size. F. Acorn globose, enclosed by scaly cup.
(Q. lyrata) OVERCUP OAK FF. Acorn ovoid, half hid in scaly cup; leaf lobes and sinuses broad, squarish.
(Q. minor) POST OAK CC. Leaves sinuately dentate with shallow sinuses; linings pale, downy.
D. Lobes of leaves acute. (Q. acuminata) YELLOW OAK DD. Lobes of leaves rounded.
E. Bark dark brown, deeply furrowed.
(Q. Prinus) CHESTNUT OAK EE. Bark light grey, scaly.
F. Limbs shedding bark in large flakes; acorns on long stalks.
(Q. platanoides) SWAMP WHITE OAK FF. Limbs not shedding bark in flakes; acorns sessile or on short stalks.
(Q. Michauxit) BASKET OAK The Blue Oak, or Mountain White Oak (Quercus Doug lasii, Hook. and Am.), is a striking and beautiful feature of the landscape of northern and central California. Silvery grey bark and pale blue foliage, deepened by greenish leaf linings, and lightened by their silvery pubescence! No wonder the blue oak attracts attention whether it stands among the scattered groves of California white oak in the broad valleys—a fine, round-headed tree—or climbs the western slopes of the Sierras till it dwindles to a shrub at an altitude of 4,000 feet. It is strangely variable in the shape of its leaves and fruit. Its leaf may have deep lobes like
other white oaks, or it may have scarcely any noticeable waves; some leaves are entire, some have pointed, even spiny-tipped lobes like those of the black oaks. The blue of them, however, is a dependable characteristic; also the silky leaf linings.
The acorns are very numerous, and so vividly green in summer that they often overcome much of the blue of the foliage until they take on their rich, chestnut brown. The nut often bulges above the saucer-like cup as if too large for it; often it is elongated into a pencil shape.
The wood is too brittle and the sap wood too thick for use in building. It is an excellent fuel.
California White Oak (Quercus lobata, N6e.)—A large, graceful tree with stout trunk dividing near the ground, with spreading top and pendulous branches, making a broad dome, 8o to too feet high, and 150 to zoo feet in diameter. Bark brown ish grey, scaly, with shallow furrows, and ridges broken into plates; twigs hoary, grey or reddish brown. Wood hard, fine grained, brittle and hard to season. Buds ovate, small, pubescent. Leaves alternate, variable, oblong or obovate, 2 to 4 inches long, deeply 7 to t 1-lobed, thin, firm, pubescent. paler beneath; petioles 193 short, broad, hairy. Flowers with half-grown leaves, February to April, staminate in hairy, yellowish catkins; pistillate, solitary and sessile, as a rule; stigmas broad. Acorns to 2} inches long, annual, sessile (rarely stalked), solitary or in pairs, conical, elon gated, sharp, horny, hairy tip; cup shallow, tomentose, with thick scales that become finer toward fringed border; kernel, sweet, edible. Preferred habitat, rich, sandy loam. Distribution, valleys in California west of Sierra Nevada Mountains. Forms open groves, never forests. Uses: Splendid feature of natural scenery, but never successfully cultivated outside of its range. Wood useless except for fuel. Fruit used as food by Indians.