EXPLANATION OF THE ILLUSTRATION 
Plate 6. Figures | through 4 are scanning electron micrographs of trans- 
verse fracture sections of artificially silicified specimens of contemporary 
Gordonia wood. Figures | through 3 show one sample after organic matter 
was removed by oxidative ‘etching’. In Figure 4, wood substance is present. 
Featured are casts of tracheid and vessel element lumina. Magnifications are: 
Fig. 1 (X500), Fig. 2 (X 1000), Fig. 3 (X 100), and Fig. 4 (X500). Figure 5 is an 
internal cast of a tracheid lumen from a specimen of lodgepole pine. This 
specimen came from a siliceous hot spring (Tree Top Pool) in the Sylvan 
Springs area of Yellowstone National Park. Prior to microscopy, organic 
matter was removed by oxidative treatment. White light photomicrograph. 
X450. 
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