oho 



36 



(b) Anatomy. 



Unlike its congener, no work appears to have been done concerning the 

 anatomical structure of the wood. 



The various sections examined show good specific differences, for instance, 

 it is seen that in the tangential section the medullary rays, whilst otherwise 

 resembling those of A . Cun^tinghamii , yet have their cells filled with the brown or 

 dark substance, the manganese compound, as shown in Figures 252-4, and the 

 perforations between the cells of the medullary rays and the lumina of the 

 tracheids, differ from those of A . Cunninghamii , being fewer in number and 

 having circular orifices. The disposition, however, of the pitted cells corre. 

 sponds with those of A. C'unninghafnii, and the simple cells communicating with 

 each lumen of the tracheids generally number about four. 



In a radial section the cells of the medullary rays are often found filled 

 with this substance, but their walls appear to be very delicate, as they break 

 easily, and stain a darker colour than those of A . Cunninghamii. They are 

 well seen in Figure 254, where it will be noticed that all the cells, both outer and 

 inner of the rays, have practically right-angled end walls, which shows, as 

 regards the character of the outer cells, a distinction from some non-Australian 

 genera of the Coniferse. 



The walls as stated above are very thin, and in sectioning are almost in- 

 variably folded over between the end walls, vide Figure 254. 



The principal features of difference in a transverse section compared with 

 A. Cunninghamii are, (i) the dark -brown content of the medullary rays running 

 through the picture like black bands, Figure 252, (2) the general absence of this 

 dark sribstance in the tracheids of the xylem so plainly seen in A. Cunninghamii. 



In Figure 254 are also shown the double rows of bordered pits in the walls of 

 the tracheidal cells. 



(d) Forestry (vide introduction to this genus.) 



V. BARK. 



(fl) Economic. 

 [Vide Chemistry, infra — Composition of the Exudation, &c.) 



(Jf) Anatomy. 



The structure of the mature bark differs entirely from that of any Conifer 

 examined during this research, or any other figured and described, so far as we 



