THE OAKS - FAMILY FAGACEAE. - Genera PASANIA and QUERCUS. Trees of great lumber and horticultural value. Leaves sim ple, alternate, entire or lobed. Flowers moncecious, inconspicuous; staminate, in pendulous catkins; pistillate, solitary or few in a cluster. Fruit, a dry nut in a scaly cup (an acorn).
KeY TO GENERA AND GROUPS A. Flowers of two sorts borne in the same cluster—an erect, crowded spike; leaves evergreen, chestnut-like.
I. Genus PASANIA, Orst.
AA. Flowers of two sorts borne in separate clusters; staminate in pendant catkins; pistillate, few or solitary on short stalks.
2. Genus QUERCUS, Linn.
B. Fruit annual; leaves with rounded lobes, not spiny pointed; bark usually pale. THE WHITE OAK GROUP BB. Fruit biennial; leaves with lobes spiny pointed; bark usually dark. THE BLACK OAK GROUP The oaks form one of the largest and noblest of the tree families. There are 30o species recognised by botanists, and this probably does not include them all. They are distributed widely over the continents of the Northern Hemisphere, and follow the mountains through Central America and across the equator along the Andes. All but a very few species are large trees, important features of the landscape and the commerce of the countries in which they grow. Among broad-leaved trees they hold a pre eminent place, and have held it from ancient times, in house and naval architecture and in bridge building. In durability, strength and toughness oak has few superiors.
Fifty species of oak are native to America; half of them dis tributed in the Eastern and mid-Continental regions, half on the Western slopes. The backbone of the continent, the main chains of the Rocky Mountains, have no indigenous oaks. No Pacific coast species is distributed also in the Eastern States, and vice versa. No European, Asiatic or American species is found outside its own continent, except as it is introduced by man.
The acorn distinguishes oaks from all other trees. It is the characteristic fruit of the family, and is found nowhere outside of it. All oaks bear acorns when they are old enough. Few begin bearing under twenty years of age.
The leaf of an oak is also characteristic. People usually learn to know an oak leaf from those of other trees without realis ing exactly how or why. There is great variety in the lobing of the
leaves, but they are all simple, alternate and almost always oval in outline, leathery, and cut by deep bays, called sinuses.
The flowers of oaks arc separate, but near together on the new shoots. The staminate are in fringe-like catkins; the pis tillate few-flowered clusters in the axils of leaves; except in the genus Pasania. The acorns are either one or two years in ripening. It happens that annual-fruited species have rounded lobes and sinuses in their leaves. Quercus alba is the type of this class, and as these trees generally have pale bark, they are known as `h.! white oak group. Biennial-fruited species have dark-coloured bark and the lobes of their leaves end in angles tipped with bristly points. They form the black oak group. Their type is Quercus velittina.
1. Genus PASANIA, Orst.
The Tan-bark or Chestnut Oak of California (Pasania den si flora, Orst.), formerly included in the genus Quercus, is now ret apart as our sole representative of an Asiatic genus of trees that stand half way between oaks and chestnuts. It is a handsome oak, decked the year round in evergreen foliage, similar in form to the chestnut. The leaves are coated, when young, with yellow pubescence, which lights up the tree as if with golden blossoms.
In summer the crown of the tree shines again with gold. The profuse staminate spikes stand erect with greenish pistillate flowers at their bases. The latter are scaly, but the nut finally rises out of a densely fringed cup, declaring itself an acorn, which takes twti years to mature, The wood of the tan-bark oak is used for fuel, but has little lumber value. Its bark, however, is more valuable to the tanner than any other. So the tree is threatened with extinction by the irresponsible bark peelers, and by forest fires carelessly set.
This tree grows along dry hillsides and in mountain ravines in California and Oregon, keeping along the coast range, and flourishing especially among the redwoods. Government pro tection of the latter would save from utter annihilation another remnant of former times, for the tan-bark oak is scarcely less interesting to the botanist than the redwood itself.
2. Genus QUERCUS, Linn.