262 



LYCOPODIALES 



[CH. 



broken up by broad medullary rays as in the common Stigmaria, 

 and in Bothrodendron the occurrence of a ring of primary xylem 

 is another peculiarity. 



In the vegetative shoots of Bothrodendron mundum the 

 stele differs from those of Lepidodendron in the narrower 

 primary xylem ring and in the large size of the metaxylem 

 tracheae ; from Lepidodendron Harcourtii and L. fuliginosum 

 the xylem is distinguished by its smoother outer face which 

 consists of numerous narrow xylem elements. 



Fio. 216. Bothrostrobus. I, ligule. (After Watson.) 



Cones of Bothrodendron (Bothrostrobus^). 



The long and narrow cones referred to Bothrodendron 

 minutifolium from English and French Coal-Measures are known 

 only as impressions and it is not possible to say whether they 

 were heterosporous or homosporous ; the drawing given by 

 Zeiller (Fig. 212, E) shows that the sporangia were of the same 



1 Nathorst (94) A. p. 42. 



