PRE-CARBONIFEROUS FLORAS. 



447 



totaxites as sufficiently proved, and be thinks that the genus 

 has been founded upon the trunks of gigantic Sea-weeds. 

 Lastly, tbe genus Cordaites is now generally regarded as an 

 ancient type of tbe Grymnosperms, thougb it is not clear 

 that it is truly Coniferous. The genus is common botli to 

 tbe Devonian and the Carboniferous formations, and includes 



Sphenoptcris laxus. Devonian. 



broad, striated, parallel-veined leaves, which are extremely 

 abundant in certain beds. They possess broad clasping 

 bases, and may attain a lengtb of a foot and a breadth of 

 as much as three inches. 



According to Grand'Eury, Cordaites is a true Conifer, the 

 sexes in whicb are in different individuals (as in the living 

 Yew-tree). The organs of reproduction are slender spikes, 

 the male ones bearing small scaly buds (supposed to be 

 antheriferous) in the axil of bracts, while the female spikes 

 carry single seeds in each axil. The same authority con- 



