MEDULLA. 9 



Having thus glanced at some of the general aspects of Stir/maria ficoides, we 

 may now examine the morphology and histology of its several parts. 



The Medulla. 



This was an exclusively parenchymatous tissue ; and, since I found it to be 

 hollow in every one of the innumerable specimens that passed under my eye, I long 

 ago arrived at the conclusion that Stiginaria possessed a fistular medulla. Owing 



bundles going to the leaves originate. In the second place, what can be more regular than the 

 dichotomy of the rootlets of the living Lycopods. I shall further show on a later page that the 

 rootlets of Stiginaria, the " feuilles rudimentaires " of M. Renault, did not disarticulate like leaves, or 

 leave a true leaf-scar. They have a distinctive internal organisation common to the - entire series, 

 respecting which M. van Tieghem, our highest authority on the structure of roots, says, " Par la 

 structure du cylindre central, et par la division dichotomique qu'on y observe en plusieurs endroits, 

 vos racines appartient bien certainement a un Lycopodiacee de la famille desSelaginellees " (' Organi- 

 sation of the Fosssil Plants of the Coal-Measures,' Memoir II, p. 294). That Stiginaria does exhibit 

 some characteristic peculiarities, is unquestionable, but they are very different from those enumerated 

 by M. Renault. 



Since writing the foregoing pages, I have ascertained, to my surprise, that even some of my 

 German friends hesitate to accept the testimony of Binney, Dawson, and others on these important 

 fundamental facts, and call for additional evidence that they are facts. This demand is easily met. 

 A few definite points are unquestionably proven. 



I. The gigantic Sigillarian stems must have had large roots. The specimens figured on my Plate I 

 demonstrate not only that they bad such roots, but that these roots branched dichotomously. 



II. It is a characteristic feature of these roots that we invariably find them separating at the 

 base of the aerial stem into four primary ones, as represented on Plate II. 



III. The specimen figured on Plate III demonstrates that, when obtained in a sufficiently young 

 Btate, these four roots were Stigmarian, bearing the characteristic rootlets of St igmaria ficoides up to 

 the base of the aerial stem which they sustained. 



IV. The Well-known Duckinfield example, now preserved in the museum of the Owens College, 

 presents four such primary roots, which dichotomise as in my Figs. 1 and 2, and though these display 

 no traces of Stigmarian structure in their thicker portions close to the central aerial stems, their 

 prolonged branches are absolutely Stigmarian. 



V. The absence of Stigmarian rootlet-scars from the proximal portions of the Duckinfield specimen 

 is manifestly due to growth. The enlargement of each root having led to the decortication of the 

 superficial cortical zone of which the exterior of the base of each rootlet was but an extension, the result 

 was the reduction of the thick, proximal end of each root to the condition of those of Figs. 1 and 2. 



We have here a few fundamental facts that it is absolutely impossible to dispute. They establish 

 the truth that the Stigmaria ficoides is a root of these large trees ; scientific evidence is rendered 

 worthless if plain observations like these, made by a number of experienced observers, is to be 

 lightly rejected. But I may add, from my own recent personal observations, that the conclusions 

 arrived at from the above five propositions were amply sustained by observations which I made in the 

 fine Carboniferous forest recently exposed at Oldham, where I found both Sigillarian and Lepidodendroid 

 stems furnished with Stigmarian roots. 



