,8,,. SI GILL ARIA AND ST I GM ARIA. 215 



examples which, so far as I understand his views (which I must 

 confess I am unable to do very distinctly), seem to be identical with 

 our British type, but to which he applies his name of Stigmaviopsis. 



Now, to all this I entirely object. Our British forms are those 

 which have been recognised as the true Stigmavia ficoides ever since 

 the days of Sternberg and Artis ; and I contend that if our French 

 friends have discovered in their coalfields a new type, it is not for 

 them to divert our old name to their new forms, but to invent for them 

 a new name, Stigmariopsis or any other, and leave us in the possession 

 of our own time-honoured title. 



Notwithstanding all that has been written by MM. Renault and 

 Grand' Eury on this subject, and which I have studied with careful 

 attention, I am still unable to understand clearly what their views 

 are, beyond their conclusion 'that some of these objects are rhizomes 

 furnished with leaves, while others are true roots. When I try to 

 comprehend which are the actual examples of the one and the other, 

 I fail to do so. Anyhow, I claim for all our British forms, ^n^, that 

 they represent the true Stigmavia ficoides of the many authors who 

 have written on the subject, and, second, that these forms are voots 

 furnished with rootlets, and not rhizomes bearing buds and leaves. 

 Imprimis, they are voots employed to fix and sustain a noble aerial stem 

 in the ground, and also to extract from that ground such nitrogenous 

 and mineral substances as the giant aerial Lycopodiaceous structures 

 require for their nutrition. 



My belief that the appendages which clothe these roots are root- 

 lets and not leaves, is shown by their organisation. Like the roots 

 of recent Lycopods, each one has a single remarkable monavch vas- 

 cular bundle, which M. Van Tieghem first showed to be so charac- 

 teristic of the roots of the Lycopodiaceae. Then they possessed that 

 remarkable root-like power and habit of distributing themselves, 

 penetrating every minute aperture into which they could, by the 

 faintest possibility, obtain an entrance, in search of nutriment, a 

 faculty which is wholly foreign to leaves of every kind and degree ; 

 besides this, the fact of their subterranean position altogether unfits 

 them for performing any foliar functions. The aerial stems and branches 

 were magnificently supplied with real foliar organs, to which the per- 

 formance of these subaerial functions was committed. Organs so 

 different in structure and disposition could not possibly be merely 

 modified homologues of an identical organ. Then we have the 

 cardinal distinction, so fundamentally characteristic of almost the 

 entire vegetable kingdom, that these roots are geotropic organs, while 

 the leaves belong to a heliotropic system. 



A further proof that the appendages to Stigmavia cannot be 

 leaves is shown by the ovigin of their vascular bundles. Those of the 

 true aerial leaves spring solely from the primary, or non-exogenous 

 xylem, which terminates at the base of the aerial stem, and never 

 enters the roots. The vascular cylinder of the latter organs, on the 



