ROOTLETS AND ROOTLET BUNDLE. 33 



the section, dividing it into two areas, each of which has a bundle and bundle sheath, 

 like those of fig. 63, in its centre. On the other hand, a s^tion of a third rootlet 

 displays the bundle divided into two, but even the bundle sheath has not yet begun 

 to divide. All these arrangements correspond very closely to what we find in the 

 branching rootlets of recent Lycopods. In the specimen figured by Artis, as well 

 as in my fig. 27, the two branches appear to be joined to the primary one by 

 oblique articulations ; but I find no trace of these in my sections. They were 

 probably mere constrictions of the cortical layer. In one section of a rootlet 

 in my cabinet the bundle is enlarged laterally in a fan-shaped manner, as if 

 preparing to divide. A union of the two bundles of fig. 63 would produce a very 

 similar contour to that seen in the above specimen. It appears as if this slight 

 tendency to dichotomous branching, manifested by the Stigmarian rootlets, was 

 the forerunner of what became a normal condition amongst recent Lycopods. 



Plate X, fig. 42, represents a transverse section of a large rootlet, g, into the 

 interior of which six smaller ones have forced their way, in doing which they have 

 squeezed the true vascular bundle and its cylinder, /, of the invaded rootlet into a 

 corner. This example affords a good illustration of the extraordinary way in 

 which these rootlets penetrated openings, large or small, in any vegetable fragment 

 within their reach. 1 



1 M. Renault lias figured a similar specimen in his " Etude surles Stigmaria, Rhizomes et Racines 

 des Sigillaires," ' Annales des Sc. Geol.,' xii, 1, PI. ii, fig. 1. Describing this specimen, he designates 

 the invaded rootlet as a leaf, whilst the invaders are admitted to be true rootlets, But he gives no 

 adequate reason for thus applying different names to things that do not differ. Comparing his figures 

 with similar specimens in my cabinet, I can only conclude that, misled by a foregone conclusion, he 

 has allowed himself, in his pages 24 — 30, to be drawn into a confused maze of errors. He does not 

 deny that his leaves and his rootlets have the same external forms and internal organisation ; the supposed 

 difference to which he trusts in distinguishing leaves from rootlets being in the form of sections of 

 their vascular bundles. It would be needless further to discuss a question with which I have already 

 alluded on p. 22, were it not for the important conclusions which M. Renault draws from his supposed 

 facts. I have already shown that the two types to which our author attaches so much importance 

 pass by imperceptible gradations into each other, and, I may add, that similar wedge-shaped and non- 

 wedge-shaped bundles exist amongst the rootlets of living Selaginellse. 



But the question assumes importance because it is made the basis of conclusions which set at 

 defiance some of the most fundamental laws of botanical morphology, relating to the positions of 

 members upon a common axis. The pages 24 — 30 contain a succession of statements which I cannot 

 accept. Describing a section like my fig. 14, Plate VII, he says that the vascular bundles which I have 

 indicated by/,/', " ne peuvent etre pris pour des faisceaux de racines, dont ils n'ont aucun des caracteres" 

 (loc. cit., p. 21). I reply that, without one solitary exception, all those bundles go to those character- 

 istic appendages of the Stigmarian axis which are now so widely recognised as rootlets. The illustrations 

 given in the preceding pages surely demonstrate that point. M. Renault further says : " Nous regardons 

 ces faisceaux comme un portion des elements vasculaires destines a des appendices foliaires " (loc. cit., 

 p. 22). "We are thus carried back to the days of Artis, Corda, and the ' Fossil Flora of Great Britain.' 

 The labours of Brongniart and Hooker, of Binney and Dawson, along with those of a host of other 

 observers are all to be cast aside as worthless. Before thus returning to the dark ages of Carboniferous 



