CORDAITALES 



171 



of fibers on both sides; the large bundles are connected by transverse 

 bridges of thick-walled cells; and the mesophyll is compact. Such 

 a form and structure is entirely unlike anything known among ferns 

 or Cycadofilicales, and certainly approximates that of the leaves of 

 Cordaites. Scott (8) says that such a leaf organization is comparable 

 to a single leaflet of such a cycad as Bowenia. 



THE ROOT 



Amyelon radicans is a root of the Coal-measures known to belong 

 to Cordaites, and often preserved in remarkable detail (fig. 203). 

 It bears irregularly arranged bunches of lateral roots, which have 

 been examined recently by Osborn (26). The thick cortex is 



Fig. 203. — Amyelon, the root oi Cordaites: p, tetrarch primary xylem; x, secondary 

 xylem showing growth rings; pk, phloem; d, periderm; Xg. — From photomicro- 

 graph of section made by LoMAX. 



divisible into two regions, the inner of which contains dark cells that 

 show fungal hyphae. The conclusion is reached that "Cordaites 

 was probably a tree inhabiting saline swamps, and having bunches 

 of coralline rootlets on its roots, such as are known to occur in many 

 recent plants growing under similar conditions." As only one case 



