214 NATURAL SCIENCE. 



II. 



The publication of a new work (Geologie et Paleontologie du 

 Bassin Houiller du Gard, 1890) by my old friend M. C. Grand' Eury 

 has again raised the question of the nature of the Stigmaria ficoides. 

 Isliy own views on the subject, based wholly upon our British speci- 

 mens, were embodied in full detail in my Monograph published in 

 1887 by the Palaeontographical Society, and nothing has occurred 

 since its appearance to require me to alter a single statement of any 

 importance which that memoir contains. In it I confined myself, as 

 I have said, wholly to the study of British examples of the plant, 

 paying no attention to the figures and descriptions of Continental 

 specimens which I had no opportunity of studying personally. 

 Hence, respecting such specimens I gave no opinion. 



M. Grand' Eury has not, either in his new figures or his des- 

 criptions, entered ipto much detail, but he has reiterated in all its 

 decisiveness the French hypothesis that the true Stigmaria are not 

 roots, but rhizomes, " qui, ayant ete incapables de se soutenir, ont 

 flotte dans I'eau ou rampe sur la vase qu'ils ont aussi penetree" 

 (p. 236). " Une fois seulement je les ai surpris divergeant d'un 

 centre sous tige." We have here a statement altogether inapplicable 

 to anything that we discover in Great Britain, His hypothesis 

 appears to be identical with the vague and speculative guesses that 

 were prevalent among us in the early years of the present century, 

 and to which the discoveries of Sir William Logan put an end. 



Whenever we discover a perfect example of our British Stigmavia, 

 like my magnificent one from Clayton now in the museum of the Owens 

 College at Manchester, we invariably find it to consist of a circle of 

 dichotomously-branching roots radiating from a centre whence ascends 

 a stem either of a Sigillaria or a Lepidodendvon ; and the recent discovery 

 of several similar, though smaller, examples at Osnabruck in Germany, 

 chronicled by M. Potonie,' are exactly of the same character. M. 

 Grand' Eury divides the objects which he discovers in France into 

 two groups. To one of these groups he gives the name of Stigmana, 

 and this he considers to be something very different from our roots 

 of Sigillaria and Lepidodendvon, to which we apply the same name. 

 He describes his Stigmarise as long rhizomes, not varying much in 

 diameter, or radiating from a common centre. Once only he appears 

 to have met with a specimen which did so radiate. The appendages 

 to these " rhizomes," unless I misunderstand him, which appear 

 to me to differ in no respect from the rootlets of our British examples, 

 he and M. Renault regard as leaves. On the other hand, he finds 



^ " Jahrbuch der konigl. preuss. geologischen Landesanstalt," 1889. 



