PLATE XV. 



Halonia regularis. 



Fig. 1 (No. 34) represents a transverse section of a root, exhibiting a disarranged 

 woody cylinder and the months of numerous vascular bundles traversing the parenchyma- 

 tous tissue, of which it was chiefly composed. From the Coal-measures near Dudley. 

 Magnified "i\ diameters. 



Fig. 2. A longitudinal section of a portion, showing the medulla, composed of 

 orthosenchyma, surrounded by a woody cylinder of scalariform tubes, from which proceed 

 vascular bundles (several of them being displayed). Magnified 4 diameters. 1 



Fig. 3. A longitudinal section of a portion of the centre of the root, showing the 

 medulla and the woody cylinder. Magnified 8 diameters. 



Fig. 4. A transverse section (at nearly right angles) of one of the vascular bundles, 

 near the outside of the root. Magnified 25 diameters. 



' The artist has represented in fig. 2 the specimen as a stem, and not as a root, as we believe it to be. 

 In order, therefore, to show the true direction of the vascular bundles leading to the rootlets, the figure 

 should be reversed. 



