i86 
Notes . 
xylon ’ structure. The leaf was thus a highly compound one; the 
structure of the leaflets associated with the rachis, agrees well with 
that of the Alethopteris leaflets, figured by M. Renault. 
The roots, never previously observed in any species of Medullosa, 
were of triarch structure, with abundant formation of secondary wood 
and bast, and an early development of internal periderm, by which the 
primary cortex was thrown off. Developmental stages show that the 
periderm originated in the pericycle. The roots, which branched 
freely, were borne on the stem in vertical series, between the bases 
of the leaves. They were attached to pedicels, through which the 
vascular tissues of the roots were continuous with those of the stem. 
The author is indebted to Mr. J. Butterworth and Mr. G. Wild, for 
specimens which have thrown important light on the connexion 
between root and stem. 
The full paper concludes with a short historical rdsume, and a dis- 
cussion of affinities. 
Medullosa anglica , in the structure of its stem, shows unmistakable 
affinities with Heterangium , perhaps the most fern-like of the genera 
grouped under Cycadofilices. The new species is far simpler than any 
Medullosa hitherto described, for the steles are not only few but are 
uniform, showing no differentiation into a peripheral and a central 
system. The small central steles, called ‘ Star-rings ’ in other Medul- 
loseae, are absent here. In these and other points the species agrees 
with the genus Colpoxylon of Brongniart, but as that genus is doubt- 
fully distinct and its leaves are not known, it is not proposed to unite 
the English species with it. 
In the structure of the petioles and the leaf generally, Medullosa 
anglica is as highly organized as any of the Medulloseae, and 
agrees closely with M. Leuckarti , the only other species in which the 
connexion between leaf and stem has been at all satisfactorily 
proved. 
In the structure of the petioles, and of the roots, in the secondary 
tissues, and in the secretory canals, which occur throughout the plant, 
there are clear points of agreement with Cycads, though the primary 
structure of the stem was that of a Fern. The affinities in the latter 
direction come out more clearly in Medullosa anglica than in any of 
the other species as at present known. 
The habit of the leaves, if as appears likely, they were of the 
Alethopteris type, must have been fern-like; but that in itself, as 
