264 LYCOPODIALES [CH. 



resembles recent Lycopods. It is impossible to decide whether 

 Watson's cone represents a more or a less primitive type than 

 Lepidostrobus : if we accept Professor Bower's views in regard 

 to the evolution of vegetative organs by the sterilisation of 

 sporogenous tissue, we should probably place Lepidostrobus lower 

 in the series than Boihrostrobus ; but the greater resemblance 

 between the fertile and vegetative shoots of Bothrodendron, as 

 compared with the more pronounced difference in the case of 

 Lepidodendron, may be regarded as an argument in favour of 

 recognising Bothrodendron as the more primitive type. 



Another possible example of a Bothrodendron cone has been 

 described by Nathorst from Spitzbergen as Lepidostrobiis 

 Zeilleri^; this appears to consist of an axis bearing spirally 

 disposed sporangia without any indication of sporophylls. This 

 strobilus may belong to Bothrodendron tenerrimum. 



Pinakodendron . 



The name Pinakodendron^ was instituted by the late Prof. 

 Weiss for a type of stem closely resembling Bothrodendron but 

 differing in the presence of a fine reticulation on the outer bark 

 and in the form of the leaf-scars. Weiss's genus has been recog- 

 nised by Kidston in Dumfriesshire but our knowledge of the 

 plant is as yet based solely on a few small specimens. 



Omphalophloios (a genus of uncertain systematic position). 

 Figs. 193, C, 217. 



This generic name was instituted by White ^ for certain 

 specimens of large stems originally described by Lesquereux 

 from the Coal-Measures of North America as Lepidodendron 

 mammillatum and L. cyclostigma. The photograph reproduced 

 in fig. 193, C, for which I am indebted to Dr Kidston*, represents 

 a specimen described by him from the Upper Coal-Measures 

 of Somerset as Omphalophloios anglicus, and identified with 

 Lepidodendron anglicum of Sternberg. 



The surface of the impression shown in fig. 193^ C is 



1 Nathorst (94) A. p. 42, PI. xii. figs. 8—10. 2 Kidgton (03) p. 797. 



3 White (98) ; (99) p. 218, Pis. lxv.— lxviii. " Kidston (02) pp. 358, 359. 



