A PALEOZOIC ANGIOSPERM 347 



spermophyton americanum " was chosen for the first-known 

 Paleozoic plant of angiospermic affinity. 



No traces of Angiosperms have previously been known below 

 the Comanchian. Our coal-ball carries the highest plant type a 

 long way back in the geologic time scale. Does it mean that we must 

 greatly modify our conceptions of plant evolution ? By no means. 

 Only the lines of descent which seemed to converge in the Mesozoic 

 take an aspect of greater parallelism which presupposes an 

 immensely removed focus, just as the sun beams appear parallel to 

 our eye and yet we know of their convergence. Succeeding dis- 

 coveries in the geologic history of plants and animals convince us 

 more and more of the long duration of the unrecorded stage of 

 evolution. 



