CORDAITEAE 521 



coal, so that the total diameter was no doubt consider- 

 ably greater in the natural state, than appears from the 

 fossil remains. 



The leaves were borne in a spiral sequence, on the 

 ultimate branches ; they were simple elongated leaves, 

 varying considerably in form in different members of 

 the group ; on these differences genera or subgenera 

 have been founded. Thus, in the typical Cordaites 

 {Eu-Cordaites) the leaves are spathulate, with blunt 

 ends ; they reached in some cases a length of a metre, 

 and a width of 1 5 cm. To this group the forms most 

 fully investigated belong (see Fig. 188). Then we 

 have Dorycordaites, with leaves little inferior in length 

 to those of the last group, but lanceolate and sharply 

 pointed. Our Fig. 187 represents a restoration of a 

 tree belonging to this subgenus. Finally there is 

 Poacordaites, with grass-like leaves, reaching half a 

 metre in length, by only a centimetre or so in breadth. 

 The leaves of Cordaiteae, whatever their form may have 

 been, are all characterised by parallel venation, giving 

 them much the appearance of Monocotyledonous leaves, 

 such as those of a Yucca or Dracaena ; consequently, 

 the earlier writers on fossil botany always placed these 

 fossils in the class Monocotyledons. The veins are 

 repeatedly forked, except in the narrow leaves referred 

 to Poacordaites. In many instances branches have 

 been found, bearing the leaves (cf. Fig. 188), or marked 

 by the scars due to their fall. The scars are usually 

 transversely elongated, and "sometimes bear the prints 

 of the vascular bundles which entered the leaf. The 

 leaves were crowded in some forms, more remote in 

 others, but there was always a free internodal surface 



