FUSTIC WOOD: ITS SUBSTITUTES AND ADULTERANTS. 11 



late wood vary from 0.03 to 0.1 millimeter and are evenly distributed 

 throughout the annual ring of growth; occasionally they are arranged 

 radially in groups of from two to four. The perforations at the ends 

 of the vessel segments resemble large simple pits. The side walls of 

 vessels have bordered pits where they are in contact with the wood- 

 parenchyma fibers or pith ray cells. The wood fibers which form the 

 bulk of the secondary wood have simple pits and vary in length from 

 0.630 to 1.302 millimeters, with an average length of 0.939 millimeter. 

 Wood-parenchyma fibers are not very abundant, occurring sparingly 

 only near vessels and invariably contain small solitary crystals in 

 each cell. The pith rays are very narrow, varying from one to three, 

 but rarely more than two rows of cells in width. (Fig. 4.) 



IDENTIFICATION OF FUSTIC WOOD AND ITS SUBSTITUTES. 



The distinguishing characters of nearly all woods are more readily 

 observed in transverse than in longitudinal sections, and for this 

 reason the illustrations in this circular show magnified transverse 

 sections of the wood of fustic, smoke-tree, osage orange, and south- 

 ern prickly ash (figs. 1, 2, 3, and 4). It is chiefly upon the characters 

 to be seen in these sections with an ordinary pocket lens that the fol- 

 lowing key is based: 



A. Layers of growth indistinct (diffuse porous). 1 



1. Tangential (wavy) bands of wood -parenchyma fibers 2 conspicuous, and con- 

 taining numerous small pores filled with tyloses. 



(a) Wood light yellow, retaining color indefinitely, moderately hard and 

 heavy (about 43 pounds per cubic foot) . Chlorophora tinctoria (fig. 1). 



B. Layers of growth distinct (ring-porous). 3 



1. Tangential bands of wood parenchyma in the late wood more or less incon- 



spicuous and interrupted. 



(a) Wood orange yellow (when freshly cut), turning brown with expo- 

 sure, hard and heavy (48.2 pounds per cubic foot). The large pores 

 in early wood are completely filled with tyloses. 



Toxylon pomiferum (fig. 2). 



2. Tangential bands of wood-parenchyma fibers entirely wanting. 



(a) Wood brownish yellow, moderately hard, and of lighter weight (about 

 40 pounds percubic foot) than the preceding. Pores in early wood 

 large and very numerous, gradually diminishing in size and num- 

 ber in the late wood Cotinus cotinus (fig. 3). 



(6) Wood pale yellow, slightly tinged with red, moderately hard, and of 

 lighter weight (31.51 pounds per cubic foot) than the preceding. 

 Pores in early wood smaller than in the preceding, forming a single 

 interrupted row, abruptly diminishing to a slightly smaller size and 

 evenly distributed in the late wood, solitary or in groups of two to 

 four Xanihoxylum clavaherculis. 



1 See footnote 1, p. 8. 



2 This tissue appears as fine lines or bands, usually wavy and often interrupted, running in the same 

 direction as the annual layers of growth, and is seen in figure 1. 



See footnote 2, p. 8. 



