FOSSIL BOTANY. 239 



spinous or acicular leaves, and terminated by scale-cones, 

 •which bore spores like the Club-Mosses. The Sigillarue 

 were likewise arboreous, but their trunks exhibit longi- 

 tudinal ribbing or fluting, and vertical rows of seal-like 

 impressions representing the leaf arrangement ; they were 

 but little, if at all, branched, and clothed with numerous 

 long, tapering leaves. 



. 4. The Conifers were represented by the genus Protax- 

 iteg, allied to the Yew ( Jbints). 



203. The Flora of the Carboniferous Age, or the 

 vegetation of the Coal-measures, is of peculiar interest, 

 both because of its great abundance and because of its 

 diversity of forms. About one-fourth of all known fossil 

 plants are from the Coal-measures. There were many 

 marine plants, among which may be mentioned the curious 

 Spiral-plant, or Spirophyton. Fungi existed at that time. 

 But the great majority of plants may be referred to the 

 groups- Equisetinse, Filices, Lycopodinse, and Coniferse. 



1. Equisetinae. Besides plants of the genus Cdlamites, 

 which has already been described, there were representa- 

 tives of other closely-related genera, as Aster ophyllites, 

 Sphenophyllum, etc., all of which became extinct in the last 

 period of the Carboniferous Age. 



2. The Ferns were abundantly represented — nearly 

 one-half of all the plants of the Coal-measures belong to 

 this order. Some of them had creeping stems like our 

 common Ferns, and others were Tree-Ferns, such as are to- 

 day found growing only in warm latitudes. A Tree- Fern 

 of the Coal-measures, called Megaphyton, had its large 

 fronds in two vertical ranks; other common genera were 

 Oyelopteris, Odontopteris (Fig 344), Neuropteris, etc., whose 

 leaflets, or pinnae, were destitute of a midrib ; Sphenopteris, 

 EymenophylKtes, etc., whose pinnse had a midrib discern- 



