OF THE FOSSIL PLANTS OF THE COAL-MEASURES. 
167 
Plate. 
Fig. 
1 
Pages on which 
references are 
made to the 
figures. 
4 
13 
radiating rootlets, d" being intersected transversely ; 
e, cortical parenchyma. Cabinet number, 1846. 
X 17 . 
A transverse section of a free rootlet, with a structure 
161 1 
4 
14 
identical with that of fig. 12, d"; a, a central vascular 
axis; 6, apparent bundle-sheath, enclosing the phloem, 
c, with the two cortical layers, d' and e. Cabinet 
number, 1844. X38 . 
A section of a second free rootlet like fig. 13 : h, 
161 
1 
. 
15 1 
apparent vascular bundle-sheath, enclosing the 
apparent phloem, c, and again invested by the two 
cortical layers, d and e. The vascular bundles are 
either those of a diarch root or they are concentric 
bundles like those of Ferns, the development of 
which began in the two foci of an ellipse of pro¬ 
cambium. Cabinet number, 1844. X 38 . . . 
Section of another and apparently younger rootlet 
1 
! 
i 
161 
16 ’ 
than 13 and 14, in which the cortical cells, e, 
are arranged in the cycloidal order common 
amongst these young rootlets : a, vascular bundle ; 
h, bundle-sheath or pericambium ; c, zone occupied 
by phloem. X96. 
Longitudinal section through the root of Rliizonium 
161 ; 
4 
17 
verticillatum : a, a central vascular bundle ; a , secon¬ 
dary vascular bundles going obliquely downwards to 
the several rootlets of each verticil c, c ; h', delicate 
parenchyma surrounding the vascular bundle ; h, 
outer cortical parenchyma. Cabinet number, 1909. 
X 15. 
Transverse section of a root like fig. 16 : a, a central 
i 
162 
vascular bundle the transverse section of which 
is triangular ; h', inner cortical cells arranged in 
cycloidal order ; h, external cortex ; c, c, c, c, c, longi¬ 
tudinal sections of the bases of five rootlets of one of 
the rootlet verticils. Cabinet number, 1907. X 65 
162 
