328 On Fossil Plants from the Coal of Lancashire, fyc. [June 15, 



In 1849, August Joseph Corda published his 'Beitrage zur Flora 

 der Vorwelt,' a work of great labour and research. Amongst his numerous 

 specimens, he describes and illustrates one of Diploxylon cycadeoideum, 

 which, although not to be compared to M. Brongniart's specimen, still 

 affords us valuable information, confirming some of that author's views 

 rather than affording much more original information. All these last 

 three specimens M. Brongniart, in his ' Tableau de vegetaux fossiles con- 

 side'rees sous le point de vue de leur classification botanique et de leur dis- 

 tribution geologique,' published in 1847, classes as Dicotyledones gymno- 

 spermes under the family of Sigillarees ; amongst other plants his Sigil- 

 laria elegans, Mr. Witham's Anabathra, and Corda's Diploxylon. 



In 1862 the author published, in the 'Quarterly Journal of the Geolo- 

 gical Society ' of that year, an account of specimens which confirmed the 

 views of the three learned authors above named as to Sigillaria and 

 Diploxylon being allied plants ; but showed that their supposed pith or 

 central axis was not composed of cellular tissue, but of different sized 

 vessels arranged without order, having their sides barred by transverse 

 striae like the internal vascular cylinders of Sigillaria and Lepidodendron. 

 These specimens were in very perfect preservation, and showed the ex- 

 ternal as well as the internal characters of the plants. 



All the above specimens were of comparatively small size, with the 

 exception of that described by Mr. Corda, which, although it showed the 

 external characters in a decorticated state, did not exhibit any outward 

 resemblance to a plant allied to Sigillaria with large ribs and deep furrows so 

 commonly met with in our coal-fields, but rather to plants allied to Sigil- 

 laria elegans and Lepidodendron. 



In the present communication the author has described some specimens of 

 larger size than those previously alluded to, and endeavoured to show that 

 the Sigillaria vascularis with rhomboidal scars gradually passes as it grows 

 older into ribbed and furrowed Sigillaria, and that this singular plant not 

 only possesses two woody cylinders arranged in radiating series, an in- 

 ternal and an external one divided by a zone of cellular tissue, both increas- 

 ing on their outsides at the same time, but likewise has a central axis 

 composed of hexagonal vessels, arranged without order, having all their 

 sides marked with transverse striae. Evidence is also adduced to show 

 that Sigillaria dichotomizes in its branches something like Lepidodendron, 

 and that, like the latter plant, a Lepidostrobus is its fructification. The 

 outer cylinder in large Sigillaria is composed of thick-walled quadran- 

 gular tubes or utricles arranged in radiating series, and exhibiting every 

 appearance of having been as hard-wooded a tree as Pinites, but as yet no 

 disks or striae have been observed on the walls of the tubes. Stigmaria is 

 now so generally considered to be the root of Sigillaria, that it is scarcely 

 necessary to bring any further proof of this proposition ; but specimens 

 are described which prove by similarity of structure that the former is 

 the root of the latter. 



