84 



FOSSIL PLANTS. 



months ago, I have discovered several upright trees in the coal-measures, evidently not 

 SigiUaria, with roots of Btigmaria united to them. These trees exhibited so many of the 

 characters of Lepidodendron that I at once concluded they belonged to that genus ; but, 

 having never seen it hinted that Lepidodendron possessed Stigmaria roots, and distrusting 

 my own skill in fossil botany, I determined to wait till I could collect more decisive evi- 

 dence in confirmation of my opinion. This evidence I have now obtained in another 

 example, fortunately most complete in all its parts, a description of which I hasten to lay 

 before the Society, accompanied with sketches, which I hope will clearly prove that the 

 stem in question is a genuine Lejjidodendron united to roots of Sfigmaria." 



§ 8. Unger, in 1847, in his 'Chloris Protogsea,' under his OxAev^^, Lepidodendrea, 

 98, Halonia, Lindl. and Hutt. says : 



" Trunci arborei cylindrici decorticati ? cinatricibus minoribus punctiformibus vel 

 rhomboideis spiraliter dispositis, majoribus tuberculatis reniotis instructi." 

 " Lindl. and Hutt., 'Foss. Flora,' ii, p. 12. 



" 1. Halonia ttibercidafa, ' Brong. Hist. Veget. Foss.,' ii, pi. xxviii, figs. 1, 2, 3. 



''Halonia tortuosa, Lindl. and Hutt., Foss. Flo., South Shields, vol. ii, pi. Ixxxv, 

 p. 11. 



" 2. Halonia gracilis, Lindl. and Hutt., Low Moor. 



" 3. Halonia Beinertiana, Gopp., p. 203, Charlottenbrun, Silesia." 



§ 4. Mr. J. S. Dawes, in some remarks on the internal structure of Halonia} states 

 that " it was proposed by the authors of the ' Fossil Flora ' that the genus Halonia 

 should comprehend all those plants combining the surface of the Lepidodendra with the 

 mode of branching of the Conifera, to which latter order they considered these fossils to 

 be analogous. The discovery, however, of better preserved, specimens has clearly shown 

 that the supposed remains of alternate branches, noticed more particularly in the species 

 H. gracilis, must have been merely impressions of the protuberances which characterize 

 these fossils, and that they are, in fact, like the Lepidodendra, dichotomous. A still 

 further proof of cryptogamic affinity is now afforded by sections of a specimen from the 

 neighbourhood of Birmingham, in which traces of the vegetable structure have been pre- 

 served. By reference to the drawing, fig. 1, it will be seen that this stem is composed of 

 a central medullary column {a), surrounded by a series of scalariform vessels {b) ; these 

 being succeeded by a compact cellular tissue (c), which becomes more lax between this 

 central part and the cortical zone, the latter {d) being composed of a thick-membraned, 

 very regular tissue, and bearing a large proportion to the rest of the stem, equal in some 

 specimens to one third of the diameter. There are no concentric rings, or, strictly speak- 

 ing, medullary rays, neither any ligneous fibre, or indeed any indications whatever of 

 affinity with the Conifera, or even with that division of the Dicotyledons, except that some 

 ' Vol. iv, pp. 289—291, of the 'Quart. Journ. Geol. Soc.,' 1848. 



