473 STUDIES IN FOSSIL BOTANY 



which are radially arranged ; the wedge-shaped groups 

 of secondary tracheides are separated from one another 

 by medullary rays, usually more than one cell in 

 thickness. The sculpturing of the tracheides consists 

 of several rows of crowded circular pits, limited to the 



O.c 



Fig. 176. — Calamopitys Satumi, Unger. Transverse section of stem, .r, primary xylem- 

 strands ; .r-, secondary wood ; o.c, outer cortex, with fibrous strands ; Lt, double- 

 leaf-traces ; pet, petiole-base, containing six bundles ; s.c, sclerenchyma at junction 

 of petiole with stem, x about 4. After Solms-Laubach. 



radial walls in the case of the secondary elements, but 

 occurring on all sides of those tracheides which belong 

 to the primary wood. 



The phloem is preserved in one fragment, and 

 contains bast-fibres, in addition to the elements of the 

 soft bast. The wide inner cortex is parenchymatous, 

 while its outer zone is strengthened by strands of hypo- 



