506 AMENTACE-E. 



Liquidambar, and is known by the name of Liquid Storax. Liquid- 

 ambar styraciflua, orientale, and Altingia, are said to be the chief 

 sources of this resin or balsam, containing benzoic acid. The species 

 of Casuarina (Cassowary-tree) yield excellent timber, called Beef- 

 wood from its having some resemblance to raw beef. What is called 

 the She-oak in Australia, is C. quadrivalvis. In the integument of the 

 seeds of Casuarinas there are numerous spiral cells. 



1036. The species of Betula, Birch, have astringent and resinous 

 barks. The oil from the bark of the common Birch (Betula alba and 

 glutinosa) gives the peculiar odour to Russia leather. In North 

 America the bark of the Canoe Birch (Betula papyracea) is used for 

 making boats. A saccharine matter exists in the sap of the Birch. 

 Betula lenta is the Black Birch of America, and is called Mountain 

 Mahogany on account of the beauty and hardness of its timber. Alnus 

 glutinosa, common Alder, grows well on the muddy ground on the 

 banks of rivers. Platanus orientalis, the Oriental Plane, has broad 

 palmate leaves, resembling the Sycamore which is often erroneously 

 called the Plane in Scotland. Some say that this is the Sycamore of the 

 ancients. Platanus occidentalis, another species of Plane, is also culti- 

 vated as a showy tree. 



1037. The Hazel-nut, with its involucral appendage, is the produce 

 of Corylus Avellana. The bark of Quercus pedunculata. (Robur), the 

 common Oak, contains much tannin, and is used as an astringent. 

 Another British species, Q. sessiliflora, having sessile fruit, is said to 

 yield the best timber. It is said that, in the wood of Q. pedunculata, 

 there are numerous medullary rays (silver-grain), (fig. 99), while in 

 that of Q. sessiliflora, Durmast, there are scarcely any visible. There is 

 some doubt as to the existence of more than one species in Britain, and 

 no permanent characters have been established. Babington mentions 

 three species. It has been stated that 2000 well-grown oaks, equal to 

 3000 loads of timber, are required to build a seventy-four gun ship. 

 The acorns of Quercus ^Egilops, Valonia or Balonia Oak, under the 

 name of Velonia, are used by dyers. Oaks are liable to the attacks 

 of insects, whose punctures give rise to the formation of galls. These 

 excrescences occur on the buds, bark, and leaves. The medicinal 

 galls are the produce of Quercus infectoria, a native of Asia Minor, and 

 the best are imported from Aleppo. They are caused by punctures 

 from the ovipositor of the Diplolepis (Cynips) Gallae-tinctorum. Blue 

 galls are those which still contain the young insect in their interior, 

 while white galls are those from which it has escaped. In medicine 

 they are employed as powerful astringents, and in the arts they are 

 used for dyeing, tanning, and forming ink. The bark (Epiphkeum) of 

 Quercus Suber constitutes cork (fig. 100). The bark of Quercus tinc- 

 toria is called Quercitron, and yields a yellow dye. Quercus Ilex, 

 Evergreen Oak, is commonly cultivated in gardens. The Oak, rrv 



