APPENDIX IV 317 



the naked eye. The pores, though not very numerous, are conspicuous ; 

 they are very irregularly distributed, singly for the most part, but also in 

 groups or rows ; and often contain resin, and have irregular areolae of soft 

 tissue. On the surface of a solid section they appear pinkish. 



Diffuse-porous woods with minute vessels are further subdivided according 

 to the presence or absence of broad pith -rays, Plane, Beech, Hornbeam, 

 Hazel, and Alder exemplifying the former subdivision. The wood of the 

 Plane (Plate XXVIII.) differs from the other four examples in having all its 

 pith-rays broad. It is light-brown, and in the American species here repre- 

 sented {Pldtanus occidentdlis) the rings are seen well defined in the section by 

 a narrow zone of dense autumn-wood. The boundary-line bends slightly 

 outwards at the pith -rays — i.e., forms a series of shallow loops between every 

 two rays, with their concavities towards the circumference of the stem. 

 The pith-rays are numerous, straight, and uniformly broad, except at the 

 boundaries of the rings, where they widen. They are lighter than the 

 ground-tissue, and shine, so as to yield a pretty figure, sometimes known as 

 ** Honeysuckle," when quartered. The pores are crowded; but those in 

 the autumn -wood are less so, and are much more minute. 



The wood of the Beech (Plate XXIX.) is very similar, but has numerous 

 excessively fine pith-rays between the numerous broad ones. The undula- 

 tions of the ring-boundaries are generally stated to curve in the reverse 

 direction to those of the Plane— i.e., with their concavities towards the 

 centre of the stem — but this does not appear to be so in our section of Idgus 

 ferruginea. The crowded pores decrease gradually in number and in size 

 towards the narrow autumn zone, the abrupt outer margin of which clearly 

 indicates the ring-boundary. ^ 



The heavy, hard, and exceptionally tough, yellowish-white wood of the 

 Hornbeam {Carpinus Betulus) is readily recognizable by the naked eye. Its 

 rings are remarkably sinuous, and it has a small number of very broad " false " 

 or compound pith-rays made up by the union of numerous narrow ones, and 

 having ill-defined lateral boundaries. They have not the shining lustre of 

 those of Beech or Plane. The pores are so far massed in the first-formed 

 spring-wood and absent in the latest autumn-wood as to mark the rings. 

 They are largely arranged in short radial lines (Plate XXX.). 



The much Hghter, soft wood of the Alder (Alnus glutinosa), (Plate XXXI.) 

 which, from white, dries to a light brown, is recognized by the few broad, 

 nearly straight compound pith-rays, with very numerous fine simple ones 

 between them, and the sHght undulations of the faint ring-boundaries, which 

 bend inward at the broad rays. The pores are somewhat fewer in the autumn- 

 wood, and show a sHghtly radial grouping. The general occurrence of brown 

 pith-flecks, which are sometimes concentric, is another discriminating feature. 



The dijffuse-porous woods with minute pores and with no broad pith-rays 

 may be subdivided into those in which the pith-rays, though narrow, are 

 quite distinct to the naked eye, as in Maples, HolHes, MagnoUdcece, Lindens, etc., 



^ For further detail see G. S. Boulger, Life-History of the Beech, Quarterly Journal 

 of Forestry, vol. i. (1907), pp. 230-279. 



