THE FLORA OF THE COAL PERIOD IN THE UNITED STATES. 



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so broad that were it not for their truncate base they would be almost orbicular. All 

 that I have seen are very obtuse, except one broad, short leaflet, which is somewhat 

 acuminate, and occurs on the same stem and close to an elongated, somewhat scythe- 

 shaped, very obtuse pinnule. Some of the larger pinnules were apparently trilobate. 

 The nervation also varies somewhat ; in all of them there exist the same, strongly pro- 

 nounced, rather distant, nearly straight nervules, but in some pinnules the tendency to 

 the formation of a median nerve is much more marked than in the others. The contrac- 

 tion of the base also varies ; in some leaflets it is so sudden and angular that the base may 

 be said to be truncate ; in these the contraction is generally most marked on the one side, 

 and the part left for attachment is broad ; in others, the larger pinnules, this contraction 

 is less abrupt, more regular, and the basal angles are rounded ; in such pinnules the at- 

 tached portion is narrow. I have dedicated this beautiful species to Prof. Lesqucrcux. 

 Coal-fields of Western Virginia, Dr. Dixon. 



