Manchester Memoirs, Vol. I. (1906), No. 10. 5 



uniform and solid, and about 2 mm. across (see Figs. 3 

 and 4). The position of the protoxylems is not absolutely 

 determined, partly owing to the preservation, partly to the 

 fact that they appear not to have been very markedly 

 differentiated from the rest of the tracheides. In trans- 

 verse sections certain rather indefinite groups of smaller 

 elements are found near to or at the edge of the stele, 

 and from the uniform appearance of the central portions 

 one may safely say that the bulk of the wood, if not all, 

 was centripetally developed (see Fig. 3). In some cases 

 such groups appear oblique, in transverse sections, and 

 they show simple scalariform markings. A number of 

 longitudinal sections were specially prepared, but in none 

 did the preservation justify the trouble. Spiral and annular 

 markings appear to be absent (or never preserved), not 

 only in the axis, but also in both petioles and roots. This 

 is not uncommon in fossil ferns, and may be a sign of 

 slow growth ; the small scalariform tracheides may well 

 be the actual protoxylem elements. The tracheides of the 

 main mass are on the whole very uniform, about 015 mm. 

 in diameter, their corners fitting closely in together. 

 The wood mass appears to be absolutely solid, as in none 

 of the sections can I find any suggestion of soft inner 

 tissue (as in Zygopteris, Racliiopteris corrugata, etc.) or of 

 xylem parenchyma. The form of the tracheides is fern- 

 like, many being simply scalariform, with one or two rows 

 of elongated pits ; the larger ones, however, show series 

 of small round pits. The larger tracheides of this type 

 show 6 — 8 rows of these pits {cf. Fig. 7), and are not 

 paralleled, so far as I am aware, in any recent fern, though 

 frequent in the Botryopterideae. 



The phloem is not preserved in most of the sections, 

 but obviously it would have lain in the space surrounding 

 the xylem. In two sections in which the axis has locally 



