The Structure of Mesoxylon Sutcliffii (Scott). 
BY 
ARTHUR J. MASLEN, F.L.S., F.G.S. 
Formerly Marshall Research Scholar at the Royal College of Science. Lecturer on Geology 
at the South- Western Polytechnic , Chelsea . 
With Plates XXXIXI-XXXVI. 
Contents. 
PAGE 
I. Introduction 381 
II. General Characters 385 
III. The Pith 391 
IV. The Leaf-traces surrounding the Pith 393 
V. The Xylem, Phloem, and Pericycle ; and the Leaf-traces passing 
through them 398 
VI. The Cortex and Leaf-bases 404 
VII. The Axillary Buds 406 
VIII. Diagnosis of the Specific Characters of Mesoxylon Sutcliffii . . 409 
IX. Conclusions 409 
Explanation of the Plates . . . 413 
I. Introduction. 
L AST year Dr. D. H. Scott, F.R.S., and I published a preliminary 
note : £ On Mesoxylon , a new genus of Cordaitales,’ 1 the object of 
which was to establish the new genus and to give brief diagnoses of the five 
species which had been recognized in preparations obtained from the 
calcareous nodules of the Lower Coal Measures of Lancashire. 
Of the five species — Mesoxylon Sutcliffii , M. poroxy loides, M. multirame , 
M. Lomaxii , and M. platypodium — one form, M. Sutcliffii , had been already 
shortly described by Dr. D. H. Scott under the name Poroxylon Sutcliffii? 
with the qualification that ‘ though the plant is certainly related to the 
French Poroxylons, its place in the same genus must be regarded as 
provisional, until the investigations now in progress are completed.’ In 
the same work some of the other species of Mesoxylon were referred to 
under Cordaites . 3 
1 Annals of Botany, vol. xxiv, 1910, p. 236. 
2 Studies in Fossil Botany, 2nd Edition, 1909, p. 51 1, Fig. 184. 
3 loc. cit., pp. 526, 551, 651. 
[Annals of Botany, Vol. XXV. No. XCVIII. April, 1911.3 
