424 PICEA. 



the height and furnished with a spire-like, sometimes rounded top. 



The primary branches are whorled (more correctly pseudo-whorled), 



often slender, elongated, twice 

 thrice ramified ; the branchlets dis- 

 tichous and mostly opposite. The 

 leaves are spirally arranged around 

 the branchlets and more or less 

 appressed to, or turned towards 

 them, but occasionally apparently 

 two-ranked and spreading on the 



Fig. 108. Transverse sectiof leaf of Picea excelsa. loW6r slde b 7 a twlst f tllG 



short petiole ; they spring from 



a distinct outgrowth (pulvinus), and are either four- sided or flattened 

 characters which mark out the species into two sections, thus : 



EUPICEA. -Leaves tetragonal, stomatiferous on all sides ; resin canals 

 one two. 



OMORICA. Leaves flattened, stomatiferous only on the upper side ; 

 resin canals two. 



This section includes only ajanemis, Breweriana, Omorica and sitchensis. 

 The Piceas form immense forests in the plains of Siberia, northern 

 Russia and the British Dominion of North America, either pure or 

 mixed with Larix ; also on the slopes of the Alps, Ural, Altai, 

 Rocky and other mountain ranges ; in other regions they are less 

 aggregated and frequently intermixed with other trees. Inhabiting 

 generally the northern portion of the temperate zone, they are among 

 the hardiest and in many respects among the most useful of trees ; 

 less striking in appearance than many of the Silver Firs, and 

 therefore, with two or three exceptions, held in lower estimation as 

 ornamental trees, they are of far greater economic value both on 

 account of the quality of their timber and for the many purposes of 

 utility for which some of the species are planted. 



The Spruce Firs are of geological t\ntiquity, although the strata 

 which contain fossil evidence of their first appearance are relatively 

 modern compared with those that bear witness to the first appearance of 

 the Gingko, the Yew, the Araucarias and Sequoias 1 The earliest vestiges 

 of them occur in the Miocene (Middle Tertiary) Age ; they seem to 

 have increased in number until Pliocene times, when the common 

 Spruce formed an ingredient of the British Flora, but subsequently 

 disappeared under the extreme cold of the Glacial period. Picea is 

 generally %'but not universally accepted as the classical name of the 

 European Spruce Fir, some maintaining that Abies is the correct name; 

 the weight of evidence, however, leans greatly in favour of Picea.* 

 * Perhaps the following lines from Virgil may help to solve the difficulty : 

 "Instar montis equum, divina Palladis arte 

 JEdificant, sectaque intexunt abiete costas." ^Eneid, II. 15. 



The locality to which these lines refer is Troy, which stood near the foot of Mount Ida, 

 now called Kas Dagh. On this mountain no Spruce Fir is known to grow, but the Silver 

 Fir (Abies) is still abundant ; differing somewhat from the European type it has been 

 felicitously named var. Equi Trojan i by Boissier. 



