46 OF WOOD IN GENERAL. 



the bark ; (iv) the wood, its colour, hardness, and grain ; (v) the 

 annual rings; (vi) the pores or vessels; (vii) the pith rays ; and 

 (viii) other miscellaneous characters, such as concentric markings 

 or false rings. Of these, the first three are not available to the 

 student of converted timber. The annual rings by their width 

 indicate the rate of growth, a character of great importance 

 as to quality, if not of great distinctive value. More than 12 

 rings to the inch, giving, as it does, 6 feet of girth in 134 years, 

 may be termed slow growth ; from 1 2 to 6 rings to the inch, 

 which would mean 6 feet of girth in from 134 to 67 years, 

 moderate ; and less than 6 rings to the inch, or 6 feet of girth in 

 67 years, fast growth. 



The absence of pores or vessels is characteristic of coniferous 

 woods. As to their size, Mr. Gamble classifies them in 7 groups : 

 extremely small, as in Box ; very small, as in Acer pictum ; small, 

 as in Haldu (Adina cordifolia) ; moderate-sized, as in Mahwa 

 (Bdssia latifdlia) ; large, as in Siris (Albizzia Le'bbek) ; very large, 

 as in Erythrina suberdsa ; and extremely large, as in many 

 climbers (Fig. 4, for instance). 



So too the pith-rays, as distinctive characters, are grouped 

 under seven types : extremely fine, as in Eiidnymus Idcems; very 

 fine, as in Ebony (Diospyros Melanoxylon) ; fine, as in Siris 

 (Albizzia Lebbek) ; moderately broad, as in Dillenia pentagyna : 

 broad, as in Plane (Pldtanus orientdlis), in which case they measure 

 i mm. ; very broad, as in some Oaks, in which they reach 

 1 mm. ; and extremely broad, as in Samara robusta. The number 

 and distance apart of the pith-rays are also characters of conse- 

 quence. When further apart than twice the diameter of the 

 pores they may be termed distant. 



There are some of these microscopic characters that are 

 eminently distinctive of large groups, such as the Natural Orders 

 into which botanists group plants. The Cupuliferce, for instance, 

 that great group to which the Oaks, Beeches, Chestnuts and 

 Hornbeams belong, have their pores in wavy radial lines or 

 queues : in the Ebendcece, or Ebony tribe, and the Sapotdcece, a 

 closely-allied tropical Order, including the Bullet- woods (Mimusops), 



