APPENDIX IV 315 



by the larger pores in tlie spring zone ; but these are not shown in our plate, 

 which only represents psrt of a ring. The pores are nearly uniformly dis- 

 tributed, are mostly small, and are sometimes grouped radially two to fiTc 

 together. The very numerous fine pith-rays bend to avoid the larger pores, 

 and there is an obscure arrangement of transverse lines of soft tissue. 



Teak {Tectona grdndis), a member of the Order Verbendcecs, presents 

 (Plate XXI.) a somewhat similar structure. Its rings are well defined, both 

 by the ring of large pores, forming about two rows, in the spring-wood, and 

 by the greater density of the later-formed part of each year's growth- There 

 are rather few^er pores in the later -formed w^ood, and they are sometimes 

 grouped three or four together. A white secretion of calcium -phosphate is 

 frequent in them. The numerous, moderately broad, equidistant pith-rays 

 are rather lighter in colour than the ground tissue. They produce a hand- 

 some silver-grain of elongated plates on a radial section. 



Including as it does the Neem-tree, the Crabwoods, Chittagong-wood, Satin- 

 wood, and Toon, as well as the Mahoganies both of the West Indies and of 

 Africa, and the so-called " Cedars " (Gedrela) of the New World, the Order 

 Melidcece is among the most important of tropical groups. Though in some 

 cases yellow — e.g., CUoroxylon — or even white, their woods are mostly red, 

 and are hard and heavy. The rings are sometimes clearly marked both by a 

 zone of large pores and by alternating lighter and softer spring-wood and 

 darker autumn -wood, as in Gedrela (Plate XXIV.) ; but the pores are generally 

 rather scanty, of moderate size, and evenly distributed ; and in many cases 

 there is no pore-circle, and the colour-zones may be only " false rings." The 

 pith-rays are not conspicuous. African Mahogany, as now in commerce 

 (Plato XXII.) is, perhaps, Kkdya grandifolia. It has its rings obscurely 

 marked by dark zones, but not by a pore-ring ; its pores evenly distributed, 

 of moderate size, solitary or in small groups, often radially subdivided, and 

 with dark contents, but with no marked areola of soft tissue ; and its pith- 

 rays with black contents to some of their cells, which, however, are best seen 

 in a tangential section. 



Cuban Mahogany (Plate XXIII.), which may be a Gedrela, and resembles 

 the woods from Panama and St. Domingo, has its rings marked by a narrow 

 zone destitute of pores. Its evenly-distributed, moderate-sized pores are often 

 subdivided or radially grouped two to four together, and are rendered more 

 conspicuous by accompanying soft tissue. Soft tissue also occurs in con- 

 spicuous, fine, light-coloured, transverse lines. The pith-rays are numerous, 

 very fine, u3xiform in width, seldom noticeably displaced by the pores, but 

 sinuous in long waves, which Mr. Stone says^ is not the case in Panama 

 Mahogany. Crabwood {Gdrapa guianinsis), which he figures, has numerous 

 short undulations. 



The Cigar-box Cedar, Gedrela odordta, of the West Indies (Plate XXIV.), 

 has sharply defined rings, with a pore-zone of two or more interrupted rows 

 of large round pores. These are sometimes partly filled with brown resin. 



^ Timbers of Commerce, p. 35. 



