96 MR. T. HICK Otf A NEW FOSSIL PLANT 



istic of the roots of existing plants. "Whether in Carboniferous 

 times the existing uniformity of root-structure did or did not 

 prevail may be an open question ; but, so far as I can learn, no 

 case other than that of Stiff maria has hitherto been adduced as an 

 instance of a root without the centripetally developed xylem and 

 phloem. And even here the authorities are not in agreement. 

 Our own great authority, Williamson*, is "fully satisfied that 

 fStifftnaricti viewed as an organ, is a root." Solms-Laubach f, 

 Schenk J, Renault §, and other continental palseobotanists, 

 however, still regard it as a rhizome. I suspect that these di- 

 vergencies are in some measure due to the fact that, while 

 Williamson looks chiefly to physiological distinctions, the 

 authorities referred to look rather to morphological ones. 

 However this may be, the specimen under description presents 

 no morphological characters suggestive of a root, and I incline 

 therefore to regard it as, morphologically, some form of stem, 

 either aerial or submerged. That it had an erect position may 

 be indicated by the circular arrangement of the vascular bundles, 

 and the uniform development of the enveloping tissues on all 

 sides ; but until the acquisition of further examples affords more 

 direct evidence, this point need not be emphasized. 



To plant anatomists, no part of the preceding description will be 

 more striking than that of the " enveloping tissues," and especially 

 that portion which contains the structures we are at present dis- 

 posed to regard as roots. Among recent plants it is known that 

 some species of Lycopodium — L. Selago, L. Phlec/maria, L. ulici- 

 folium ||, for example — and some Perns — Anffiopteris and Ma- 

 rattia*[\ — have roots running in the cortical tissues of the stem, 

 and a similar phenomenon is met with in some Marattiaceous 

 Ferns of Carboniferous age **. In the species of Lycopodium 

 and the Ferns referred to, these roots arise from the pericycle of 



the stem, near its summit in the one case, and from the base of 

 each leaf in the other, originating in one or more initial cells, by 



* "Stigmaria ficoides," Palseontographical Society's Publications, 1886, p. 1- 



The italics are Williamson's. 



t 'Einleitung in die Palaophytologie,' p. 296 (Engl. ed. p. 288). 



\ ■ Die fossilen Pflanzenreste,' p. 97. § ■ Cours de Botanique fossil©.' 



|| Sachs, ■ Text-Book of Botany,' 2nd English ed. p. 4G2. 



% Goebel, * Outlines of Classification and Special Morphology/ English ed. 



p. 258. 



** Schenk, * Die fossilen Pflanzenreste,' p. 27. 



