On Medullosa pusilla. 



223 



also been observed in M. anglica (Scott, '99, p. 89, Plate 5, Phot. 1, Plate 6, 

 Phot. 5). On the outer side it thins out, or may even be interrupted, 

 perhaps in connection with the departure of a leaf-trace bundle. The 

 medullary rays are numerous, with the tracheide-bands between them only 

 1-3 elements in width. 



The longitudinal section shows something of the primary as well as the 

 secondary wood. In both, the tracheides have multiseriate bordered pits, 

 sometimes ranged in as many as six rows. One or two narrow scalariform 

 or spiral elements can also be recognised in the outer part of the primary 



x 80 



Text-fig. A. — Approximately radial section of part of secondary wood, showing 

 tracheides with multiseriate bordered pits and muriform medullary rays. Drawn 

 by Mr. G. T. Gwilliarn. x about 80. Scott Coll. 2818. 



xylem. The secondary wood is cut approximately in the radial direction, and 

 several medullary rays are shown ; they are muriform, with very low cells ; 

 the pits adjacent to the ray-cells are elongated radially (text-fig. A). The 

 wood is in all respects similar to that of M. anglica. Only one leaf -trace 

 bundle is shown in connection with the stelar system, and in an undivided 

 condition (fig. 3, It.). It measures about 650 x 570 fi. There is no obvious 

 secondary wood, and the smallest elements appear to be directed outwards, 

 but the preservation is imperfect. 



R 2 



