308 A HANDBOOK OF CONIFERS 



The genus is naturally divided into two groups, characterized 

 as follows : — 



1. Eu Picea. — Leaves more or less four-sided, with stomatic 

 lines on all four surfaces. 



2. Omorica. — Leaves flattened. Stomata usually on the 

 inner surface only. 



Wood soft, resonant, odourless, long-fibred, fine, medium- or 

 coarse-grained, white or rarely pinkish, slightly resinous, resin 

 ducts few and scattered, visible with a lens, heartwood and sap- 

 wood not well marked, knots often loose ; works well, takes glue 

 well, and finishes with a satiny surface. Distinguished from fir 

 {Abies) by the presence of resin ducts. Apflications numerous, 

 including general indoor joinery and carpentry, aircraft construc- 

 tion, boxes, scaffold poles, pit-props, sounding-boards for violins 

 and other musical instruments, the tops of kitchen and dairy 

 tables, matchwood, match-boxes, toys, carving, paper pulp, 

 and, when split into shavings, for the manufacture of hats and 

 baskets. " Burgundy pitch " is the refined resin of P. excelsa 

 and " Swiss turpentine " is distilled from the leaves and branches. 

 " Spruce " or " Spruce beer " is a fermented liquor made from 

 an extract of the twigs and leaves of spruce mixed with treacle 

 and other sugary products. The pliable roots have been twisted 

 into ropes and fishing lines. 



Spruces succeed in wet, cold, and shallow ground, and are 

 suitable for places where pines will not grow. They withstand 

 a good deal of exposure and are fairly good windbreaks. They 

 bear shade well when young. When planted close together the 

 small lower branches die and fall away naturally, the trees develop- 

 ing with long, slender, clean trunks. Under forest conditions 

 spruces are usually spaced 3| or 4 ft. apart. Isolated specimens 

 may retain their lower branches until late in life. Spruces are 

 unlikely to succeed on hot dry land or in the vicinity of smoky 

 towns. Several species form handsome decorative trees, and 

 they are employed for that purpose in parks and gardens. On 

 low-lying land in exposed places the soft young shoots are some- 

 times injured by late spring frosts. The spruces are propagated 

 by seeds which may be sown in pots or boxes, or, when large 

 numbers of plants are needed, in well- prepared nursery beds 

 during March or early April. Seedlings may stand two years 

 in the seed-bed if not very close together, and must then be lined 

 out in nursery borders. For forest work, permanent planting 

 should be carried out when the plants are 9-12 in. high ; in gardens, 

 specimens 3-4 ft. high can be used, provided they have been 

 transplanted every alternate year while in the nursery. Well- 

 grown, healthy trees should be selected as seed-bearers. 



Spruces are sometimes injured by aphides. Chermes ahietis, 

 an aphis covered with a white, fluffy exudation, punctures the 



