240 



SYSTEMATIC BOTANY. 



able only towards the 

 base, and from which the 

 veins did not branch ; 

 Aleihopteris, Pecopteris, 

 Asplenites, etc., whose 

 pinnae presented a distinct 

 midrib, from which the 

 nerves branched more or 

 less obliquely. 



3. The Lycopods 

 were represented by huge 

 Lepidodendra (Fig. 345), 

 and other nearly-related 

 genera, as well as by gigantic SigiUarim. The roots of 

 these plants are often found fossil, and are distinguished 

 by scattered, rounded depressions, or elevations. These 

 were formerly believed to be leaf-scars on stems and 

 branches ; and the genus Stigmaria was formed to'inelude 

 them. They are yet designated by this name, but they 

 have in many cases been found attached as roots to the 

 Lepidodendra and SigiUaricB. Fruits also have been 





found, generally isolated, but they are believed to be the 

 fruits of the preceding plants. 



Fig. 344. Odontopteris Wortheni (Carbonifer3us Age). Fig. 346, Lepidode»- 

 dron diplotegioides (Carboniferous Age). 



