778 DR R. KIDSTON AND PROF. W. H. LANG ON OLD RED SANDSTONE PLANTS 



Text-fig. 1. — Psilophyton princeps, Dawson. 



"Restored section of magnified stem, showing (a) scalarifomi axis, (6) woody cylinder, 

 (c) cellular cylinder, (d) outer fibrous cylinder." (Dawson, I.e., p. 90, pi. xi, lig. 127 ) 



The letters placed below the figure indicate our int -^rotation of Dawson's reconstruction. 

 o.c, outer cortex ; i.e., inner cortex ; ph., phloem ; x. , xyle 



/33^ 



/31+": 



I if** 



/3U-~k 



/3U-^. 



Text-fig. 2. — Psilophyton princeps, Dawson. 



" Fig. 133. — Rhizoma, transverse sections showing axis. Natural size. 



" Fig. 134. — The same magnified. 134a, scalariform tissue ; 1346, woody fibres ; 134c, bark 

 fibres. 100 diams." 



