ORGANIZATION OF THE FOSSIL PLANTS OF THE COAL-MEASURES. 7438 
Mr. Nerup’s specimen thus affords a certain amount of evidence that Lyginodendron 
Oldhamium, or some allied species, may have attained the dimensions of a small tree. 
As regards the habit of the ordinary small specimens, with which we are familiar, 
the radial symmetry of the stem and the fact that adventitious roots, when present, 
are given off on all sides, render it probable that the plant grew in an upright 
position. The longest piece of stem which we have is barely three inches (7°6 centims.) 
in length (C.N. 1207 A). The position of the nodes in this specimen is not very 
evident ; two, however, can be distinguished and they are about one inch (2°5 
centims.) apart. 
From the course of the vascular bundles we know that the total length of the 
stem must have included many internodes, for, if our interpretation of the facts be 
correct, it follows that each transverse section of the stem usually shows the traces 
of the next ten leaves above. We must, therefore, picture Lyginodendron to 
ourselves as having a tall, upright stem rising to a height of several feet and bearing 
somewhat remote, spirally arranged, highly compound, fern-like leaves. The base of 
the stem, where the adventitious roots were given off, must have been buried for 
some depth in the earth or mud. Probably the bases of stems would be the parts 
most often preserved, which would explain the frequency with which adventitious 
roots are met with in connection with the stem. It is not probable that the roots 
were aérial; the fact that they branched freely immediately on leaving the stem 
militates against such an idea (see photograph 10, fig. 18). The velamen-like 
outer layer, which might suggest an aérial root, is common to the finest rootlets, 
and these must almost certainly have been subterranean. ‘The well-developed xylem 
of the roots renders it probable that they vegetated in a fairly firm soil. 
The stem is mechanically well-constructed and thus fitted to maintain an upright 
position while bearing abundant foliage. We have no distinct evidence for any 
rhizome-like organs, but it is possible that some of the small shoots which are rather 
deficient in sclerenchyma may have been creeping or subterranean. The small 
specimens, which constitute almost the whole of our material, could not have been 
branches borne on main stems, for in that case they would not have borne adventitious 
roots. If the plant really attained a relatively large size, then we must assume that 
our material is made up of young specimens. 
This brings us to the most important of all questions, that as to the fructification. 
It is a remarkable fact, that though Lyginodendron Oldhamium is one of the 
commonest of our English coal-fossils, and though all its vegetative organs are pre- 
served with astonishing perfection, no certain traces of reproductive organs have 
ever been discovered. 
If the plants constituting our material had borne anything at all of the nature of 
a cone, it is difficult to understand why its remains should never have been found. 
The only cone-like body discovered had, as we have shown above, nothing to do with 
the fructification. 
