14 



COLOMBIAN MAHOGANY. 



The cavities of wood-parenchyma fibers of Cariniana (fig. 5, a) are 

 usually filled with hardened, compact starch grains, certain resin 

 derivatives, and crystals of calcium oxalate (fig. 5, h). These 

 crystalline bodies appear in long perpendicular rows or irregular- 



C Tti&ii^r 



Fig. 9. 



Fig. 10. 

 Fig. 9. — a, a, Two segments of a vessel; '. \vood-parenchyma fiber; all separated from the wood of Swietenia 



mahagoni; c, shows complete absorption of the cross walls of each segment of a vessel; d, bordered pits. 



Magnified about 100 diameters. 

 Fig. 10. — Wood fiber (separated) of Swietenia mahagoni, showing cross partitions at a. Magnified about 



100 diameters. 



shaped nodules or angular granules, though generally they occur in 

 a great variety of forms, tetragonal crystals being the most abundant. 

 Each crystal is inclosed in a cubical crystal sac, and of which there 



