Dixon-^- Mahogany ', Recognition of some Different Kinds. 433 



tlie maximum diametric measurement is 0'15mm.-0"12mm. The medullary rays 

 are also of very different sizes in different mahoganies, and may average 1*5 mm. 

 in height : e.g., in Lumbayao (PI. XL1V., fig. 133), to 0-35 mm., e.g., in some 

 West Indian. Also the number of cells forming the thickness of the 

 medullary rays may be very different. For instance, in Guatemalan 

 (PI. XXVIII., fig. 41) the rays are usually but a-single cell in thickness, 

 while. in African mahoganies they are often seven cells thick, and may be 

 eight or even nine (Pis. XXX.-XXXIL, figs. 50, 56, 63). 



These structural differences have led to rather confusing and contradictory 

 statements as to the anatomical characteristics of " mahogany." Gamble (8), 

 in a description of mahogany, says : — " Annual rings marked by a continuous 

 line of pores, with few or no pores in the autumn wood." Stone, commenting 

 on this statement, remarks : — "A continuous pore-ring can only be found in 

 the so-called cedars, and then only in the light and softer kinds, such as 

 Mexican cedar, and they have invariably pores scattered throughout the 

 autumn or late wood (i.e. the outer side of the annual ring)." In contradiction 

 to this view, both Marshall Ward (20) and Boulger (2) classify mahogany 

 with the ring-porous woods; but the latter states: — "The vessels in the 

 summer wood [are] but little smaller than those in the spring wood." There 

 is no doubt that in many mahoganies the vessels are uniformly scattered over 

 the whole cross section, while in others they are grouped in zones. We may 

 even find this variation in different samples of wood coming from the same 

 species, e.g., Swietenia mahagoni L. (PI. I, figs. 1 and 4) has uniformly scattered 

 vessels ; in fig. 4 the vessels are grouped in zones, leaving the intervening 

 regions almost free from vessels. 



Such differences in the different woods classed as mahogany might be 

 multiplied, and it might seem that either the name mahogany ought to be 

 abandoned altogether and distinct names given to the different timbers now 

 classed under it, or it should be restricted, as Mell (10) suggests, in its use to 

 the wood to which it was originally applied, i.e. to the timber derived from 

 Swietenia mahagoni and possibly also ixomS. macrophylla. But the abandon- 

 ment of a term so widely used is quite impracticable ; and its restriction to the 

 timber of the tree from which mahogany was first obtained is also not feasible, 

 for, according to Stone (16), it is even uncertain if any of the timbers now on 

 the market come from Swietenia. mahagoni L., and certainly most of them do 

 not. Another course is to so define the term " mahogany " as to include most , 

 if not all, the timbers at present recognized under that name in commerce, and 

 at the same time exclude as far as possible similar woods which, differing 

 demonstrably from the " true " or original mahogany, are not generally 

 considered to be mahoganies. 



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