REMAINS OF STEMS OF DOUBTFUL AFFINITY, ETC. 363 



even more doubtful than that of Lyginodendron. It cannot well be 

 reckoned with Cycadeae on account of its central primary bundle ; and on 

 the other hand, if there were no secondary growth, there would scarcely be 

 any reason for doubting that it is of the nature of Ferns. The large and 

 few leaf-bundles are against its belonging to plants resembling Lycopo- 

 diaceae, such as Williamson 1 has suggested. But the near affinity to 

 Lyginodendron is obvious. 



A quite peculiar and still little known genus is Kaloxylon 2 , Will., which 

 was discovered by its author in the Lancashire calcareous nodules, and was 

 subsequently obtained in some specimens from the Burntisland nodules, 

 which are from a much lower part of the series. It consists of axes of very 

 small diameter, and with their centre occupied by a uniform vascular strand. 

 This strand, the only one present in young specimens, shows a somewhat 

 polygonal outline, and is surrounded by a secondary growth formed of 

 wedge-shaped portions not more than six in number, which are traversed 

 by ordinary medullary rays of one row of cells, and are separated from one 

 another by broad gaps or rays. Each gap or ray is wedge-shaped by 

 increase of breadth towards the outside and is filled with parenchyma, 

 and, according to Williamson's 3 description and figure, answers to a bay in 

 the line of cambium. The rind outside of this cambium-zone is parenchy- 

 matous, and according to Felix 4 , who examined sections of Kaloxylon 

 from the Langendreer nodules, is full of lacunae ; two layers of somewhat 

 broader fibre-like elongated cells are developed on the extreme outside. As 

 regards the character of the tracheal elements of the wood of Kaloxylon, 

 Williamson says that it belongs to the ' reticulated type.' But this expres- 

 sion is very indefinite, for the English author refers to this type not only 

 true reticulated vessels, but very often also bordered pit-elements, in which 

 owing to imperfect preservation only the outer line of the border of the 

 pit is visible, as for example in Lyginodendron and Heterangium. In a 

 rather oblique transverse section obtained by the author himself I thought 

 I saw scalariform vessels ; but the specimen departs a little from the de- 

 scription in other respects, so that I do not quite trust to the determination. 

 Of the affinities of this fossil, which Williamson seeks in Lycopodinae, 

 nothing at all certain can in my opinion be for the present said. 



Lastly must be mentioned here certain fossil remains from the Carboni- 

 ferous formation, which probably represent roots of unascertained genera of 

 Gymnosperms, and which have been described by Williamson 5 under the 

 name Amyelon radicans. Like many more sections of roots which cannot 

 at present be determined, they occur not unfrequently in the calcareous 

 nodules of Langendreer and England, and often reach a considerable thick- 



1 Williamson (l),iv, p. 405. 2 Williamson (1), vn, p. 13; tt. 5-7. 3 Williamson (1), 



vn, t. 6, f. 32, and t. 7, f. 34. * Felix (2). 5 Williamson (1), v, p. 67. 



