THE FOSSIL OSMUNDACE^]. 665 



We have again to express our indebtedness to the Executive Committee of the 

 Carnegie Trust for an additional grant to defray the cost of the plates necessary to 

 illustrate this part. 



DESCRIPTION OF FIGURES. 



The figures are all from untouched photographs. 



The following lettering is used throughout: xy., xylem; prx., protoxylem ; xy. sh., xylem sheath; ph., 

 phloem ; pr. ph., protophloem ; per., pericycle ; era., endodermis ; C, cortex ; l.t., leaf-trace ; r., root. 



Plate I. 



Fig. 1. Thamnopteris Schlechtendalii. Transverse section of specimen, o. xy., outer xylem ring ; 

 c. xy., central xylem ; i. C, inner cortex ; sc. C, sclerotic outer cortex ; i. par., inner parenchyma of petiole ; 

 o. par., outer parenchyma of petiole; Scl., sclerotic ring of petiole; r., root. x 2. (Slide 1279.) 



Plate II. 



Fig. 2. Thamnopteris Schlechtendalii. Surface view of type specimen. (Photograph by Mons. R. 



Koch ; forwarded by Mons. M. Zalessky.) Half nat. size. 



Fig. 3. Thamnopteris Schlechtendalii. Surface view of the block investigated. About natural size. 



Fig. 4. Thamnopteris Schlechtendalii. Another view of the same block showing impressions of roots, r. 

 About nat. size. 



Fig. 5 a and b. Osmunda cinnamomea. Branching root-systems dissected out from coating of petiole 

 bases. Nat. size. 



Fig. 6. Thamnopteris Schlechtendalii. Portion of stele in transverse section, x 13. (Slide 1281.) 



Fig. 7. Thamnopteris Schlechtendalii. Longitudinal section of stele showing departure of a leaf-trace 

 and of a root stele. x 7. (Slide 1285.) 



Fig. 8. Thamnopteris Schlechtendalii. Transverse section of the peripheral tissues of the stele. x 50. 

 (Slide 1281.) 



Plate III. 



Fig. 9. Thamnopteris Schlechtendalii. Longitudinal section of a portion of the outer xylem ring. 

 x75. (Slide 1285.) 



Fig. 10. Thamnopteris Schlechtendalii. Tracheae of the outer xylem ring in longitudinal section to 

 show the multiseriate pitting. x 200. (Slide 1285.) 



Fig. 11. Thamnopteris Schlechtendalii. Portion of the central xylem in longitudinal section. Contrast 

 with fig. 9. x 75. (Slide 1285.) 



Figs. 12 and 13. Thamnopteris Schlechtendalii. Tracheae of the central xylem in longitudinal section 

 to show reticulate pitting. x 200. (Slide 1285.) 



Fig. 14. Thamnopteris Schlechtendalii. Transverse section of a portion of the sclerotic cortex of the 

 stem. xl50. (Slide 1281.) 



Fig. 15. Thamnopteris Schlechtendalii. Longitudinal section of the same. x 150. (Slide 1285.) 



Fig. 16. Thamnopteris Schlechtendalii. Transverse section of departing leaf-trace. x 15. (Slide 

 1281.) 



Fig. 17. Thamnopteris Schlechtendalii. Transverse section of departing leaf-trace. Xylem almost free. 

 x 15. (Slide 1281.) 



