PAST HISTORIES OF PLANT FAMILIES 117 



The roots of Lyginodendron, when young, were like 

 those of the Marattiaceous ferns, their five-rayed mass 

 of wood being characteristic of that family, and different 

 from the type of root found in most other ferns (cf. fig. 786 

 with fig. 35 on p. 60). Unlike fern roots of any kind, 

 however, they have well-developed zones of secondary 



Fig. 783. Transverse Section of Root of Lyginodendron 



w, Five-rayed mass of primary wood ; s, zone of secondary wood ; c t cortical 

 and other soft tissues. 



wood, in which they approach the Gymnospermic roots 

 (see fig. 786, s]. 



A further mixture of characters is seen in the vascular 

 bundles of the petioles. A double strand, like that in 

 the lower Gymnosperms, goes off to the leaf base from 

 the main axis, but in the petiole itself the bundle is like 

 a normal fern stele, and shows no characters in transverse 

 section which would separate it from the ferns. Such a 

 petiole is illustrated in fig. 79, with its V-shaped fernlike 

 stele. On the petioles and stems were certain rough, 

 spiny structures of the nature of complex hairs. In some 



