CONIFERALES 



321 



absence of longitudinal parenchyma. In longitudinal radial aspect 

 it manifests a kind of pitting which is only partially araucarian, 

 for more often than 

 not the pores are 

 separated by con- 

 siderable intervals 

 and fail to alternate 

 (Fig. 229). It is 

 only occasionally 

 that the typical ar- 

 aucarian crowding 

 and alternation are 

 present. More- 

 over, in woods of 

 the Brachyoxylon 

 type wounding 

 brings about the 



formation of trau- 



FIG. 229. Longitudinal section of the wood of 

 Brachyoxylon. 



matic resin canals 

 (Fig. 230) such as 

 appear after injury in 



certain of 



FIG. 230. Transverse section of the wood 

 of Brachyoxylon formed after wounding. 



the Abietineae and in the 

 genus Sequoia. 



After the consideration 

 of the conditions in the 

 mature wood of living and 

 extinct representatives of 

 the araucarian conifers, we 

 may now turn our atten- 

 tion to the organization of 

 the xylem in the conserv- 

 ative organs of the exist- 

 ing araucarian conifers. 

 Fig. 231 illustrates the 

 structure of the wood in 

 the root of A gat his australis 

 in a region not very remote 

 from the primary wood. 



