84 



MISS NELLIE BANCKOET ON SOME 



Fig. II. Transverse section of tlie xylem of the Block I. stem. Note tLe unlseriate medullary rays. 



X 275. 

 13. Transverse section of the xylem, showing its endarch nature, a, the passing-out of a leaf- 

 trace ; b, the pith with secretory sacs, x 50. 



^ 



13. Transverse section of the periderm-like tissue shown in position in fig. 10^ b. x 50. 



14. Transverse section of the ground-tissue of the Williamsonian stems, showing secretory sacs. 



X 50. 



15. A tracheide of the Block I. stem^ showing multiseriate fitting, x 350. 



16. TransYcrse section of the Block II. Williamsonian stem (see PI. 9. fig. 1). a and b, probable 



leaf-traces ; c, leaf-base. X 3. 



17. Section of part of Block II,, showing a^ longitudinal section of Williamsonian stem ; 



by oblique sections of coniferous wood ; c^ the petiole shown on PI. 9. fig- 7. Nat. size. 



18. Diagrammatic representation of two conditions of the petiolar vascular system ; in b the 



arms of the U are slightly closer than in a^ seeming to correspond to the closer setting of 



the pinnae. X 20. 



Plate 9. 



Fig. 1, Williamsonian stem of Block II. Note the zones of large and small scars, a^ Dictyozamiies 



falcatus. Nat. size. 



2. Conifer ocaulon stem of Block III. Slightly reduced. 



3. Fronds of Block I. a, P tilophyllum cutchense; b^ frond-apex ; c, P. acutifolium ; d^ upper 



surface of P. cutchense. , Nat. size. 



4. Williamsonian stem of Block 1, a, scar; ^ and ^', levels of sections figured on PI. 8. figs. 9 



8c 10. Note slight variation in size of leaf-bases, seen at the right-hand side of the 



stem. Nat. size. 



8. fiff. 7. X 20. 



:f. PL 8. fig. 4, 5). X 20. 



7. Transverse section of a petiole showing arracgement of bundles (c/. PI. 7. fig. 13). X 20. 



8. Transverse section of a leaf-base, a, two vascular bundles shown in fig. 9 {cf. PI. 7 



figs. 17 & 18 j PI. 8. fig. 8). X 20. 



9. Two vascular bundles shown at a, fig. 8. x 100. 



.0. Portion of transverse section of Williamsonian fructification. X 100. 



