348 



DICOTYLEDONES. 



? -catkin has not more than 5 flowers (single-flowered dichasia, in which only 

 the central flower is developed). The scales on the cupules are no doubt leaf- 

 structures in this case also. According to another theory, the scales are hair- 

 structures ; they arise on the internal face of the young cupule apparently in 

 descending, but really in ascending order. The rirn of the cupule gradually 

 expands. In the <j> -flower (Fig. 335) the loculi of the gynoeceum, together with 

 the ovules, are not developed until after pollination. The leaves in all cases 

 have a divergence of f ; the lowermost leaves on the shoots are reduced to 

 stipules which serve as the bud-scales (5 rows). The laminae are conduplicate, 

 as in Corylus, and the external side is the broadest. The cotyledons are fleshy 

 and remain underground. 200 species. Paaania (100 species). 



368 species, in temperate climates, especially in Europe and N. America. 

 Authenticated forests have been found in the Oligocene. The Beech has one 

 species, Far/us sylvatica, in Europe ; it is a most important forest tree (in 

 Denmark the most important) and reaches its most northern limit near Alve- 

 sund in Norway (60 N.L.), its northern boundary line passing from Alvesund 

 in a zig-zag line through Ludwigsort, south of Konigsberg, in Prussia, to- 

 wards the Crimea. According to Steenstrup and Vaupell, the Beech did not 



B 



FIG. 335. Quercus : A 9 -flower in its cupule 

 (mag.); B longitudinal section through A, 

 showing cupule, perianth, and inferior ovary. 



FIG. 336. Fruit of Quercus. 



make its appearance in Denmark until a comparatively recent time, the Oak 

 then being partially supplanted. Other species of Beech are found in N. 

 America and Japan. Several species of Nothofagus occur in the South West 

 of S. America, and in the colder regions of the southern hemisphere. The 

 Oaks grow especially in temperate regions, e.g. in Western Asia, N. America, 

 and the mountains of Mexico. Evergreen species are found in Tropical Asia, 

 Himalaya, Japan and the Mediterranean region. In this country there is one 

 species of Oak (Q. robur), of which there are three varieties (Q. pedunculata, 

 intermedia, sessili flora). The Eating-chestnut is found in the South of Europe, 

 but is cultivated in the midland and southern counties of England. USES. 

 The wood of these trees is very useful as timber. The wood of Q. tinctoria 

 has a yellow colouring matter (Quercitron-wood). The bark of the Oak contains 

 a large quantity of tannic acid, and is used for tanning ; for this purpose 

 also the cupules of Q. vallonea, (f/jilops, grteca, and others from the Eastern 

 Mediterranean, are used under the name of " Yalloons." The Cork-oak 

 (Q. suber ; S.W. Europe) is the most important tree from which cork is obtained, 



