DESCRIPTION OF THE PLATES 



PLATE I 



FIG. 1. Diagram representing portions of two rings (pith side 

 down, transverse section.) The horizontal dotted lines indicate 

 boundaries of concentric, terminal Parenchyma (c). The 

 small circles indicate the pores or vessels which are more or 

 less evenly scattered in the upper ring, but incline to be 

 arranged in oblique lines in the lower ring. In the latter case 

 the pores of a wood under a low magnification will appear to 

 be arranged in a " herring-bone " fashion. The dots around 

 the pores indicate the Parenchyma (a), which in this case is 

 an ill-developed form in aureoles or borders to the orifices. 



FIG. 2. Portion of a ring (transverse section) limited by concen- 

 tric terminal Parenchyma (c). The peri vasal or vasicentric 

 parenchyma, which we term P. (a) for the sake of brevity, is 

 well developed and extends laterally to continuous lines 

 linking the pores together. 



FIG. 3. Another form of Parenchyma (a), where the lines linking 

 the pores are strongly undulating and usually much inter- 

 rupted. These waved lines we term " festoons." 



FIG. 4. Portion of a ring with pores sheathed with Parenchyma 

 (a) a little better developed than in fig. 1, inasmuch as it 

 extends occasionally to short wings. 



FIG. 5. Portion of the transverse section of a wood showing 

 Parenchyma (6), i.e. that which is disposed concentrically 

 (tangentially), but in the form of small bars from ray to ray. 

 The vertical lines represent the rays. Note that two of the 

 rays terminate as " thin ends." The number of such thin ends 

 between two " middles " is often a good diagnostic feature. 



FIG. 6. Diagram of rays in tangential section. The ray to the 

 left is more or less regular in shape ; the other two are " dis- 

 torted." 



FIG. 7. Radial groups of vessels (in transverse section) joined 

 by Parenchyma (a) into a group. The vessels are, however, 

 quite separate and independent of each other. 



FIG. 8. Radial ' mother-and-daughter " groups of vessels sur- 

 rounded by Parenchyma (a). The vessels are closely pressed 

 against each other as though they had arisen from the 

 subdivision of the same mother cell. 



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