1760 



A TEXTBOOK OF THEORETICAL BOTANY 



morphology of the cupule is open to various interpretations. The female 

 flower itself has a tricarpellary gynoecium and generally six perianth seg- 

 ments. Pollination is anemophilous and eventually only one ovule matures 

 so that the fruit is a one-seeded nut with a hard pericarp, the acorn, which 

 is embedded in the cupule. 



The genus Castanea contains about forty species which are distributed 

 throughout the northern temperate regions. C. sativa, the Spanish chest- 

 nut, is extensively grown in Britain (Fig. 1641). The fruit consists of three 

 nuts enclosed in a prickly cupule. These nuts are edible and have earned 

 the tree the popular name of the Sweet Chestnut. The wood is valuable as 

 timber and the bark in tanning. 



■I' 



Aid) 



Fig 



1641. — Castanea sativa. Sweet Chestnut. A, Male flower. 

 B, Cyme of three female flowers within the involucre which 

 becomes spiny. (After Wettstein.) 



[ 



The genus Fagus contains only four species, of which F. sylvatica, the 

 common Beech, is the best known (Fig. 1642). It forms homogeneous 

 woods, particularly on chalk, and is widely distributed throughout Europe. 

 Though deciduous when grown as a tree it is noticeable that when kept cut 

 as a shrub the Beech retains its withered brown leaves till the new ones open 

 in the spring, a fact made use of by gardeners in planting Beech hedges for 

 protecting young plants against wind. 



Several varieties of the Beech are known. The Copper Beech differs 

 in having a red pigment in the epidermal cells, the quantity of which varies 

 considerably and hence the tint of the tree. Another variety is the Cut- 

 leaved Beech in which the leaves are greatly dissected. Both varieties 

 originated as mutations. Beech flowers (Fig. 1643) only produce fertile 

 fruits once every few years. 



The genus Nothofagus is restricted to twelve South American and 

 Australasian species and is the southern counterpart of the genus Fagiis in 

 the north. N. ciinninghami, the Myrtle Tree, produces valuable timber as 

 does N. fusca, the Red Beech, in New Zealand. 



Fagus and Ouercus appear to be of ancient origin for fossil remains have 





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