236 PLANT-LIFE 



nian, reached its greatest abundance in the Carbon- 

 iferous, and seems to have tailed off and become extinct 

 in the Permian Period. Many species have been 

 described. A restoration of Lepidodendron elegans is 

 shown in Fig. 72. The vertical trunk grew unbranched 

 to a great height, and was crowned with repeatedly 

 two-forked ramifications. The leaves, which were 

 linear, or needle -like, were, in some instances, about 



s.c. 



FIG. 73. LEPIDODENDRON VELTHEIMIANUM : PART OF STEM -SURFACE. 

 ' L U>., Leaf -bases; s.c., leaf -scar. 



6 inches long; they were spirally arranged on the young 

 stems and branches, being seated on rhombic leaf- 

 cushions. These leaf-cushions were persistent, and it 

 is they which give the characteristic appearance to the 

 pieces of stems which are so well known to fossil collec- 

 tors (see Fig. 73). The fructifications were conelike, 

 and borne on the ends of branches or on the stem; they 

 consisted of sporophylls protecting sporangia. It has 



