OAK 551 looms. The school statistics in 1873 were as follows: 709 primary schools, with 28,166 male and 2,089 female pupils ; one female academy, with 826 pupils ; a state literary institute, pon- tifical seminary, and Catholic college, having 504, 62, and 291 students respectively. The state library, in the capital, contains 13,000 vol- umes. Oajaca is divided into 25 districts. II. An inland city, capital of the state, in the de- lightful valley of the same name, on the left bank of the Atoyac, 210 m. S. E. of Mexico ; lat. 17 10' K, Ion. 97 30' W. ; pop. about 25,000. The streets are spacious and regular, and the houses substantially built, and for the most part neat in appearance, though many of them are of adobe. The principal buildings are the ca- thedral, the Santuario de la Soledad and other churches, and convents, gorgeously decorated, the cabildo or city hall, and the episcopal palace. There are several handsome squares or plazas, embellished with trees and flowers; and the surrounding country is exceedingly picturesque, being literally covered with gardens and cochi- neal groves. Education is zealously promoted. The general hospital is said to be one of the best organized in the republic. The chief oc- cupations of the people are the manufacture of sugar, beer, indigo, cane rum, and especially of cacao, for which this city is celebrated, and the preparation of cochineal. Palm-leaf hats are extensively made, and silk weaving employs a small number of hands. Oajaca was injured by an earthquake on May 11, 1870. OAK (Ang. Sax. ac the English name of trees of the genus quercus. Some botanists place all the trees and shrubs which have their unisexual flowers in catkins in one family, the amentacea, while others, including Ameri- can authorities, make several families, placing quercus, the oak, fagus, the beech, castanea, the chestnut, and two less known genera, in a family by themselves, the cupuUfera, which thus restricted comprises trees (rarely shrubs) the fruit of which consists of nuts contained in an involucral cup (whence the name) or de- hiscent capsule. The genus quercus consists of trees and shrubs with alternate simple leaves and monoecious flowers ; the staminate flowers are in slender, usually pendulous, often inter- rupted catkins, the bracts or catkin scales fall- ing early, their flowers consisting of five to twelve stamens within a two- to eight-parted calyx. The fertile or female flowers are soli- tary or clustered; they have a three-celled ovary with two ovules in each cell, and a three- lobed stigma, and are surrounded by an invo- lucre of small imbricated scales ; in fruit the ovary becomes, by abortion of two of the cells and all but one of the ovules, a one-seeded nut (acorn), surrounded at its base by a woody cup, which is formed by the enlarged and in- durated scales of the involucre to the ovary. In his elaboration of the genus, Alphonse de Candolle gives more than 250 accepted species of quercus, some of which have several well marked varieties, and a number of doubtful species. Oaks are found over nearly the whole northern hemisphere, except the extreme north, and in the tropics along the Andes and in the Moluccas. There are both deciduous and evergreen species, presenting a wonderful difference in their leaves and general aspect, some being small shrubs, but all readily recog- nized by their peculiar fruit, consisting of an acorn and a cup, which never completely en- closes the nut. Some of the oaks furnish val- uable timber, and one species yields cork. (See CORK.) Tannic and gallic acids are abundant in the oaks, and the bark of many is valuable for tanning, while in some these principles are developed in a remarkable degree in the galls produced by the punctures of insects. (See GALLS.) The nuts not only supply human food, but that of various animals. In England in early times the acorns were regarded as the most useful product of the tree, and wooded property was valued according to the number of swine it would support. In some of our western states the mast, or " shack," is an im- portant element in the production of pork. In the Atlantic states there are about 20 accepted species of oak, with about as many sub-species or varieties. The species vary so much that the genus is puzzling to botanists, and its diffi- culties are increased by the production of seve- ral natural hybrids. The character of the wood is affected by the soil and locality in which the trees grow, and lumbermen make distinc- tions not recognized by botanists. In some of our oaks the flowers of spring perfect their fruit the same autumn ; hence the acorns ap- pear upon the wood of the season's growth, in the axils of the leaves, and often raised on a peduncle or stalk. These are called annual- fruited oaks, and the group is also marked by other characters : the leaves when not entire have their lobes or teeth destitute of bristle- like points; the abortive ovules are found under the seed ; the kernel is often sweet, and the timber is more valuable than that of the next section. The biennial-fruited oaks per- fect their acorns the year after flowering. After the staminate flowers fall, the pistils un- dergo little change, but remain until the fol- lowing spring, when they mature and ripen about 18 months after blossoming. In these oaks the ripe fruit is found below the growth of the season ; the peduncles are short or none, and the kernel bitter ; the abortive ovules are at the top of the seed ; the leaves when not entire have their lobes terminated by bristle- like points. Each of these sections is subdi- vided into several smaller groups, character- ized by the foliage. Beginning with the an- nual-fruited species, the white oak (Q. alba) is one of the most useful as well as most generally distributed. In this, as in others, the leaves present much variety, and trees growing side by side often have leaves sufficiently unlike to belong to different species; they are always deeply lobed, with the lobes obtuse ; they are pubescent below when young, smooth when
