erect or incurved, dilated above, stigmatic on the inner face or at apex only, generally persistent on the fruit; ovules anatropous or semianatropous, 2 in each cell. Fruit a nut (_acorn_) maturing in one or in two years, ovoid, subglobose, or turbinate, short-pointed at apex, 1-seeded by abortion, marked at base by a large conspicuous circular scar, with a thick shell, glabrous or coated on the inner surface with pale tomentum, more or less surrounded or inclosed in the accrescent cupular involucre of the flower (_cup_), its scales thin or thickened, loosely or closely imbricated. Seed marked at base or at apex or rarely on the side by the abortive ovules; cotyledons thick and fleshy, usually plano-convex and entire. Quercus inhabits the temperate regions of the northern hemisphere and high altitudes within the tropics, ranging in the New World southward to the mountains of Colombia and in the Old World to the Indian Archipelago. Two hundred and seventy-five species have been described; of the North American species fifty-four are large or small trees. Of exotic species, the European _Quercus Robur_ L., and _Quercus sessiliflora_ Salisb., have been frequently cultivated as ornamental trees in the eastern United States, where, however, they are usually short-lived and unsatisfactory. Many of the species are important timber-trees; their bark is often rich in tannin and is used for tanning leather, and all produce wood valuable for fuel and in the manufacture of charcoal. _Quercus_ is the classical name of the Oak-tree. CONSPECTUS OF THE NORTH AMERICAN ARBORESCENT SPECIES.