1035 
Affinities of Sutcliffia . 
throughout, the resemblance to the internal cortex of Sutcliffia insignis 
being very close. Small leaf-trace bundles occur in groups of two or three 
sparingly scattered throughout the series ; the extraordinarily few bundles 
present compared with the size of the stem are accounted for by the fact that, 
owing to the deep-seated nature of the periderm, the bundles become cut off 
immediately they enter the cortex. In all cases where the phloem is 
preserved the leaf-trace strands are seen to be concentric in structure 
(Text-fig. 3). 
Each of these ultimate leaf-trace bundles is partially surrounded by 
three or four strands of fibrous elements, differing in size, and where in the 
upper sections of the series the cortex is preserved, similar strands occur. 
In intimate connexion with the sclerenchyma strands secretory elements are 
frequently found ; these appear to be of the same type as those prevalent in 
the ground tissue. A similar association of secretory elements with fibrous 
strands is seen in Sutcliffia insignis } and has also been described by Seward 
as characteristic of Sutcliffia Williamsoni 2 (= Rachiopteris Williamsoni). 
The vascular system of the stem is essentially similar to that of 
5 . insignis ; there are, however, two important additions. The main stele 
and all the vascular strands with the exception of the small leaf-trace 
bundles are characterized by a wide zone of secondary wood and bast. In 
addition to this numerous extrafasclcular arcs of wood and bast encircle the 
vascular system proper. The preservation of these arcs leaves much to be 
desired in many cases, but there is little doubt that in life they formed 
a complete, irregular, anastomosing network around the cylinder, strongly 
recalling the extrafascicular strands of certain genera of Cycads (PI. XCI, 
Fig. i, and Text-figs. 4 and 5). 
The single main stele, which is roughly triangular in outline, varies but 
slightly in size throughout the series, except where vascular strands are 
given off, or where fusion of a neighbouring strand with the main stele 
is taking place. 
The primary wood is in all essentials precisely similar to that of 
Sutcliffia insignis , that is, the tracheides mixed with parenchyma extend to 
the centre, and the protoxylem occupies the exarch position (cf. Text- 
figs. 6 and 7). 
The dimensions of the primary wood are somewhat smaller than 
in Scott’s specimen, as would be expected from the smaller size of the 
fossil as a whole. The maximum dimensions of the primary wood of 
the new specimen are 1-4 x i-i cm. as compared with 47 x i-8 cm. in 
5 . insignis. Secondary growth has added considerably to the thickness 
of the wood, so that the total wood measurement amounts to 2-9 x 1*9 cm. 
1 Scott : loc. cit., p. 480 
2 Seward, A. C. : On Rachiopteris Williamsoni , sp. nov., a New Fern from the Coal Measures. 
Ann. Bot., vol. viii, 1894, Plate XIII, Figs. 3 and 8. 
3 Y 2 
