DAWSON SIGILLARIA, CALAMITES, AND CALAMODENDRON.. 161 



Fig. 9. Sternbergia, pith of the same, natural size ; 9 a, discigerous tissue of the 

 same. 



10. Another stem, prohaWy Coniferous, with Stembergia pith. 



11. Woody tissue of prostrate Sigillaria; 11a, bast-tissue of the same. 



12. Woody tissue of a Sigillaria ; 12 a, medullary ray. 



13. Tissue of a Stembergia similar to fig. 9. 



14. 15, 16. Discigerous tissue of erect trees (Sigillariee) in mineral charcoal. 



Plate IX. 



Fig. 17. Calamodendron approximaium, cast of pith; 17a, lib, discigerous and 

 scalariform tissue of the same. 



18. Calainodendron invested with woody tissue : A, pith ; B, woody cylinder ; 



18 a, cross section ; 186, cross section, magnified, showing compression 

 of the tissue ; 18 c, discigerous and pseudo-scalariform tissue of the 

 same. 



19. Portion of a multiporous vessel of a true Catamites, magnified to the 



same scale with figs. 17a & Ylb. 



20. Stem of erect Calamodendron (S. Joggins, Nova Scotia), showing its 



external surface, one-third nat. size. 



21. Base of stem of Catamites (S. Joggins), showing rhizoma, reduced. 



22. Node of Catamites, showing scars of verticillate branchlets and of radial 



processes. 



Plate X. 



Fig. 23. Eadial section of stem of Sigillaria of the type of S. Brownii, Dawson, 

 restored, natural size : a, pith ; b, woody cylinder ; c, cellular inner 

 bark ; d, fibrous bark ; e, outer cortical layer. 



24. Kadial section of the woody cylinder, magnified (letters as above) ; and 



portions of the tissues more highly magnified below : b 1, inner pseudo- 

 scalariform cylinder ; 6 2, 3, 4, discigerous outer cylinder. 



25. Eadial section, more highly magnified, showing one of the radiating 



bundles of vessels (this section has been inverted) ; 25 a, single pseudo- 

 scalariform vessel from radiating bundle. 



26. Tangential section of the same stem, showing the woody fibres and one 



of the radial bundles, and the medullary rays. 



27. Tangential section showing woody fibres and medullary rays, more 



highly magnified. 



28. Radial arrangement of woody fibres, magnified. 



29. Fibres or elongated cells of the bark {d). 



Note. — All the drawings of separate fibres and vessels in the above figures are 

 on one scale. , 



VOL. XXVII. PART I. 



