ACORN, OR OAK NUT.--The fruit of the oak, Quercus (_Cupuliferæ_), monœcious, evergreen and deciduous trees and shrubs, with alternate and simple straight-veined leaves. A very large genus, of about two hundred and fifty species, mainly in the temperate region of the northern hemisphere. There are some forty species native of the United States. The nuts are, on the whole, rather too harsh and bitter flavored to be esteemed or considered edible by civilized nations at the present day, but in former times some of the oak nuts were often an important article among the garnered food of the household. They were used--and are still, in some countries--boiled, roasted, and even ground and made into bread and cakes. They have also been used as a substitute for coffee, and for malt in making beer. Strabo says that in the mountains of Spain the inhabitants ground their acorns into meal, and Pliny affirms that in his time acorns were brought to the table with the dessert, in Spain. Every student of English history is well aware of the importance of the acorn, not only as food for man, in Great Britain, in the time of the Druids, and later, but also for feeding swine, deer, and other wild and domesticated animals. But with the advance of civilization and the production of better food, the oak nut ceased to be classed among the important culinary supplies. There are, however, a few species of the oak yielding nuts fairly edible in their raw state, and these are much improved by roasting. The best of those among our native species are to be found in the varieties of the white oaks of the North, and in the evergreen (_Quercus virens_) of the Southern States. But with so many far superior species of edible nuts, it is very doubtful if any of the oaks will ever be cultivated for their fruit. AUSTRALIAN CHESTNUT.--The seeds of a large tree, native of Australia, the _Castanospermum australe_, the name of the genus being derived from _Kastanon_, chestnut, and _sperma_, a seed, because the seeds resemble, in size and taste, the common chestnut. But the tree belongs to the bean family (_Leguminosæ_), and the seeds are produced in large, long pods. They are about an inch and a half broad, somewhat flattened, and of the color of a chestnut when ripe. They are roasted and eaten by the natives, but are rather unpalatable to those who have been accustomed to something better in the way of edible nuts. These seeds are also known as "Moreton Bay chestnuts."