iiinute Structure 
Growth rings . — The growth rings tend to be poorly defined, sometimes indicated 
only by a flattening of the fibers (6, 18, 2\\, 29). 
Vessels. — The individual vessels are relatively small, oval to nearly round in 
cross section, and not distinct without magnification, "hey are numerous, 
evenly distributed, solitary or in radial groups of 2 to L vessels. They have 
simple perforations. The vessels frequently contain yellowish gum but no 
tyloses (17, 18, 22, 29). 
Rays . — The rays are fine and often indistinct without magnification. Although 
the marginal cells are not markedly upright, the rays are classed as heteroge- 
neous, mostly biseriate (occasionally 3 cells vri.de at the middle), and may be 
6 to 2^ but are generally 12 to lp cells high. Low rays, rarely over 6 ceils 
high, are usually found to be uniseriate (18, 29). Ripple marks and gum ducts 
are absent (18, 29). 
Parenchyma . — Parenchyma is sparingly developed about the vessels and may often 
contain calcium oxalate crystals (18, 29). 
Fibers . — Grovrth zones may be somewhat defined by rows of radially flattened 
fibers. The fibers are libriform and nonseptate with simple pits. They have 
relatively thin walls. Fiber dimensions are recorded as follows: length, 1 
to 2 mm. (av. 1.5 mm.); diameter, 12 to 26 mm. (av. 19 mm.) (5, 18 3 2U, 29). 
Wood Composition 
Avodire wood is composed of ash, b,.5>6 percent; fats and waxes, 0.80 percent; 
cellulose, 62. 1^ percent; lignin, 32. h9 percent (all on a dry-weight basis). 
On digestion with NaOH in 5 percent concentrations for 8 hours under a j ressure 
of 3 kilograms, avodire gave a light, brownish-yellow pulp, which bleached 
easily and yielded 37 percent of bleached pulp (5, 2a). 
Rept. No. R1905 -9- 
