OAK OF ECONOMIC PLANTS. 291 



amounts to about 6000 cwts. In consequence of these large im- 

 portations of Nux Vomica, it has been thought that it was 

 used by brewers to give a bitter taste to ales. Tliis, however, has 

 been disproved, but, as the consumption for medicinal purposes 

 is but small, it is still unknown to what use the bulk is put. 



Oak. — This name is typically represented by numerous 

 species of the genus Quercus of the family Cupuliferse. About 

 20 species of other families are also called Oak, all of which w411 

 be found noticed under their respective vernacular names. 



The following is a brief notice of the principal economic 

 species : — 



1. Black American, also called Black Jack (Q. nigra), a tree 

 attaining a height of about 30 feet, having a very black bark, 

 native of IsTorth America. 



2. Belote {Q. Ballota), an evergreen tree 20 or 30 feet high, 

 native of Southern Europe and North Africa, also of Palestine. 

 Its acorns are large and sweet, forming an important article of 

 food, either raw or boiled. Ornaments are made of the cups. 



3. Black {Q. tinctoria), a deciduous tree, attaining a height 

 of 80 to 100 feet, native of the United States. Its bark is 

 black, and is used for tanning and for dyeing leather a brilliant 

 yellow, which is effected by a principle contained in the bark 

 called Quercitrine. 



4. British (Q. sessiliflora and Q.pechtncidata), forms or varieties 

 of Q. Robur. These tw^o forms are found to differ in the quality of 

 the timber, and in the acorns of the first being without a foot- 

 stalk, while in the second they hang loose. Both are natives of 

 this country and throughout Middle and Northern Europe. The 

 Oak was venerated by the Druids, and in ancient parks some 

 trees have attained a great size and age. The principal use of 

 Oak timber is for shipbuilding. The wood of Q. sessiliflora is 

 heaviest and toughest, that of Q, peduncidata being like chest- 

 nut is much used by cabinetmakers for ornamental work. Oak 

 bark is used for tanning leather, and of all the substances known 

 for that purpose that can be had in quantity British Oak bark is 

 found to be the best ; but the home supply falls far short of the 



