742 G wynne- Vaughan. — On Solenostelic Ferns. 
Fig. 14. Pteris data , v. Karsteniana. Ditto. A piece is supposed to be cut 
out of the side of the solenostele so as to show the internal vascular system. Note 
that a small strand lying within the second vascular ring is also present. The 
stem is radial. 
Fig. 15. Cyathea Brunonis. Diagram showing the arrangement of the vascular 
strands in the petiole : a ., b. and c. indicate those below which the internal vascular 
strands of the stem are inserted. 
Fig. 16. Cyathea Brunonis. Diagram of one side of the acroscopic half of a 
leaf-gap ; seen from within, and showing the insertion of the internal strands of the 
stem, a ., b. and c. 
Fig. 17. Dicksonia Barometz. Portion of the vascular system of the stem; 
seen from within, and showing the departure of three leaf-traces. 
Fig. 18. Alsophila excelsa. Diagram of vascular system of a young plant in 
median longitudinal section. The xylem is black, the phloem lightly shaded and 
the endodermis is indicated by a dotted line. The ground-tissue is left white. 
Fig. 19. Davallia aculeata. Diagram of vascular system of rhizome including 
a node and the base of a leaf-trace : ph! ., internal phloem. The external phloem 
is not indicated. The upper surface of the rhizome would face the observer. 
Fig. 20. Davallia aculeata. Transverse section of the stele of the rhizome in 
the middle of an internode : scl'., sclerenchymatous internal ground-tissue. 
Fig. 21. Davallia pinnata. Diagram as in Fig. 19. The vascular system is 
supposed to be curved so that the two cut ends face the observer more or less 
obliquely: ph'., internal phloem. 
Fig. 22. Davallia pinnata. Transverse section of the stele of the rhizome in the 
upper part of an internode : scl. and scl'. , sclerenchyma belonging respectively to 
the external and internal ground-tissue. 
Fig. 23. Davallia repens. Transverse section of the stele of the rhizome at 
a point immediately above the leaf-gap. The petiolar bundle has not yet become 
free. 
Fig. 24. Davallia repens. Transverse section of the vascular bundle of the free 
petiole. 
Fig. 25. Davallia tenuifolia. Ditto : Hk., adaxial hook of the xylem. 
Fig. 26. Davallia Speluncae. Ditto: Hk ., as in Fig. 25; Cp ., cavity- 
parenchyma. 
Fig. 27. Dicksonia davallioides. Portion of a transverse section of the soleno- 
stele : Cp., cavity-parenchyma. 
Fig. 28. Dicksonia apiifolia. Portion of a transverse section of the solenostele. 
Fig. 29. Dicksonia apiifolia. Cells of the cavity-parenchyma sending protrusions 
into a disintegrating protoxylem element of a young petiole. 
