112 



ELEMENTARY BOTANY. 



(d) The Conifers were represented by the genus Protaxites, 

 alHed to the Yew {Taxus). 



4. The flora of the Carboniferous Bra, or the vegetation 

 of the Coal-measures, is of peculiar interest, both because of 

 its abundance and its diversity of forms. About one-fourth 

 of all known fossil plants are from the Coal-measures. There 

 were also many marine plants, among which may be men- 

 tioned the curious Spiral-plant, or Spirophyton. Fungi ex- 



V i 



I 





Fig. 131. 



Fig. 132. 



isted at that time. But the great majority of plants may be 

 referred to the following groups : 



(a) Equisetaceee. — Besides plants of the genus Calamites, 

 which has already been described, there were representatives 

 of other closely-related genera, as Asterophyllites, Spheno- 

 phyllum, etc., all of which became extinct in the last period 

 of the Carboniferous era. 



(b) Filices. — ^The Ferns were abundantly represented — 

 nearly one-half of all the plants of the Coal-measures be- 

 long to this group. Some of them had creeping stems like 

 our common Ferns, and others were Tree-ferns, such as are 



