CARBONIFEROUS PERIOD. 



341 



Another group of Coal plants is the AsteropJiyllites family, having some 

 resemblance to Equiseta. It includes flexible herbaceous species, with leaves 

 arranged in a circle or whorl at joints in the stem, whence the name, from aarrjp, 

 star. They are confined to the Upper Coal measures. In the genus Aaterophyl- 

 litcs the leaves are slender; and in Sphenophyllum (from the Greek a^^a wedge) 

 they are obtuse and wedge-shaped, being smallest at base. Fig. 5S2, A*tero- 

 phyllites sublevie ; fig. 581, A. ovatus, with the nutlets in the axils of the leaves; 

 fig. 578, Sphenophyllum ScJilotJieimii Brngt., from Pennsylvania, Salem and 

 Gate veins, and Pomeroy beds, Ohio. Dr. Newberry regards some species of 



Flowers, and Fruit. 



both genera as parts of the same plant, the former the submerged part, and the 

 latter that which is emerged or rests upon the water. Anmdaria is another 

 genus of this family. One species of it is represented in fig. 616 B. 



Figs. 538-590 represent branches, with what seem to be the remains of flowers 

 and fruit, discovered by Dr. Newberry in the Ohio Coal measures. Some speci- 

 mens of this general character have been regarded by Hooker as young or par- 

 tially-developed leaf-buds. It is, however, difficult, according to Dr. New- 

 berry, to explain the specimens on that hypothesis. 



The species of Coal plants of the American coal fields, thus far 



