598 



FOSSIL PLANTS OF THE CARBONIFEROUS SYSTEM. 



dites (figs. 798, 799) and Selaginites. Some fossil species allied to 

 these are grouped under the genus Lepidodendron (tevls, a scale, and 



SlKojov, a tree) (figs. 800, 

 801). They appear to 

 occupy an intermediate 

 place between Coniferse 

 and Lycopodiaceae. Their 

 leaves are arranged in the 

 same manner as some of 

 the Coniferse, and their 

 scars are similar. Their 

 branches bifurcate like 

 Lycopodiaceag. They occur 

 in the form of dichotomous 

 trunks, 20 to 45 feet high, 

 with linear or lanceolate 

 leaves (fig. 801) like those 

 of some species of Lyco- 

 podium and Eutassa. The 

 stem consists of a thin cuti- 

 cle, a double cellular zone, 



a hollow vascular cylinder, and a pith. The tissue in the outer part of 

 the double cellular zone is arranged like that of ferns, the vascular 

 cylinder is about ^ of an inch thick, and consists of polygonal tubes 

 marked with lines, while the pith is composed of fusiform cells. The 

 stems are marked with rhomboid and orbicular scars (fig. 800). Their 



Fig. 798. Lycopodites (Walchia Schlotheimii), a plant allied to Lycopoditun. 

 Fig. 799. Lycppodites (Walchia hypnoides), another Lycopodiaeeous plant. 

 Fig. 800. Lepidodendron crenatum, with the scars of the leaves on its stem. It belongs to a 

 family of plants apparently intermediate between Coniferse and Lycopodiacese. 

 Fig. 801. Lepidodendron elegans, with its dichotomous trunk, and linear acute leaves. 



