OF THE FOSSIL PLANTS OF THE COAL-MEASURES. 
161 
plant differing materially from any that I have hitherto described. The fragments 
are very Protean in form and structure, though possessing certain remarkable features 
in common. 
Fig 9 (Plate 3) represents one of the most characteristic of these. It is a section 
of a branching stem or rhizome of the plant enlarged 14 diameters. At A the section 
has crossed a branch obliquely, revealing a central vascular axis, «, composed of very 
fine vessels of the reticulated or pitted type, some of which are fully '01 of an inch 
in diameter. The inner cortex, h', is composed of longitudinal lines of parenchymatous 
cells with transverse septa. At B is a bifurcating branch, with its vascular axis a 
also bifurcating, composed of a dense mass of vessels partly barred, but some of which 
are reticulate, like those of A, a, though of smaller diameter, some of them not being 
more than '00125 of an inch in diameter. The inner cortex, 6", resembles that of A, a, 
but the cells are of much smaller dimensions. More externally we have at h' a dense 
cortical zone composed of elongated prosenchymatous cells. A small branch with a 
central vascular bundle appears to have been given off vertically at c ; there seems to 
have been a similar one at cl, and there may possibly have been a third at e. F is 
obviously a tranverse section of either a branch or a root, the vascular bundle of 
w'hich occupies its centre surrounded by an inner cortex, enclosed within a more 
dense external one. The two external surfaces, g' and g, are densely clothed with 
numerous very large, curved multicellular hairs. The basal cells of some of these hairs 
are fully '005 of an inch in diameter, whilst some of them are fully '014 of an inch 
long. Conspicuously cylindrical throughout the greater part of their length, they are 
tapering, slender. Fig, 10 furnishes a carefully drawn representation of these hairs, 
as they appear at B g, g, enlarged 43 diameters. 
Fig. 11 (Plate 2) is a transverse section of one of these stems enlarged forty-four 
diameters, its mean one being '009 of an inch. In its centre, a, is a cluster of 
tracheids, the entire cluster being about '02 of an inch in diameter, enclosed within h, 
which appears to occu]:)y the position of a true bundle-sheath. These tracheids are 
reticulated like those of fig. 9. A narrow zone of delicate parenchyma, c, lies between 
the tracheids and the supposed bundle-sheath, vdiich may either have a circumferential 
phloem or a procambial tissue. The inner cortex, d, consists of a very regular thin- 
walled parenchyma, which, in turn, is invested by e, a coarser prosenchymatous tissue. 
Externally to this prosenchyma are numerous transverse isolated sections of hairs, f, 
of varying diameters. The most striking feature of this section consists of the remains 
of four radiating appendages g, g', g", g". The most perfect of these is g, in which we 
discover the central vascular bundle a invested by the two cortical layers d' and e. 
These radiating appendages, taking their rise from what has been either the peri- 
cambium or the endoderm, and forcing their way through the cortical tissues of the 
primary axis without receiving any contributions from those tissues, can, I think, only 
have been either roots or secondary rootlets. 
Fig. 12 is an oblique transverse section through a stem similar to fig. 11, the lower 
MDCCCLXXXIX.—B. Y 
