OF THE FOSSIL PLANTS OF THE COAL-MEASURES. 
683 
Even had I no further evidence to offer as to the fem-like character of these petioles, 
it would be impossible to overlook their very close resemblances to those of many recent 
ferns. The form of their vascular bundles is not widely dissimilar from that of Asple- 
nium nidus , whilst their bands of subepidermal fibres represent the continuous layer of 
the sclerenchyma of Mettentus and other authors, so common in many ferns. The 
epidermal surface of Pteris umbrosa is covered with small rounded protuberances like 
those shown in the transverse sections of our fossil. But fortunately we are provided 
with further testimony. Many of my sections display evidence of the association of 
leaves with these petioles; but the two represented in Plate LII. fig. 13, and Plate LIII. 
fig. 14, from sections made by Mr. Butterworth, are the finest of this class that I have 
hitherto met with. 
Plate LII. fig. 13 is evidently part of the upper extremity of a frond giving off lateral 
pinnules. In the large central rachis we have at a the vascular bundle, and on each side 
of this we have the bark with its characteristic masses of dark-coloured cells (i) and its 
epidermal tubercles (Jc"). Two lateral pinnules are given off at x, x, and fragments of 
similar pinnules are scattered throughout the entire section. Each pinnule divides 
into groups of terminal leaflets ( l ), each of which leaflets is supplied with a central 
vascular bundle ( m ) prolonged from the central vascular axis (a). Numerous similar 
but detached leaflets (l 1 ) are scattered over the section. 
Plate LIII. fig. 14 represents either one of these lateral pinnules or that consti- 
tuting the terminal portion of a rachis in a still more perfect state. The central 
vascular bundle of the rachis (a) sends branches into each of the lateral pinnules (x), 
and which again subdivide to reach the several terminal leaflets (l). The general 
aspect of these sections suggests the idea of a young half-developed frond in a semi- 
circinate state. It is very difficult, if not impossible, to determine with absolute cer- 
tainty the exact type of fern to which this specimen belongs. The mode of subdivision 
of the lateral pinnules is more suggestive of a Sphenopteris than of a Pecopteris or a 
JS T europteris. The leaflets seem to have been grouped in small radiating clusters rather 
than on the regular bilateral plan of an ordinary Pecopteris ; at the same time this 
apparent irregularity may but be the result of a section passing through a plant dis- 
torted through pressure. The rounded form of the numerous transverse sections of 
leaflets (fig. 13, l") seen in the specimens suggests the idea of the latter being very 
succulent, with a vascular bundle penetrating the centre of the parenchymatous mass. 
Another circumstance connected with these objects originally suggested the possi- 
bility that the plant might have been a bipinnate frond of the type of Pecopteris. At 
an early period of my researches my attention was arrested by the frequent occurrence, 
in the nodules from which these specimens were obtained, of objects like Plate LII. 
figs. 15 & 16, associated almost invariably with long narrow lines of beaded structures 
like the upper parts of Plate LIII. fig. 17 and the left-hand side of fig. 18. The 
former of these structures (fig. 16) consisted of a doubly curved object like a section 
of a young leaf having a re volute vernation. These objects were generally about T 
mdccclxxiv. 4 z 
