Affinities of Helminthostachys zeylanica. 445 
EXPLANATION OF FIGURES IN PLATES 
XXI-XXIII. 
Illustrating Messrs. Farmer and Freeman’s paper on Helminthostachys. 
Fig. 1. Naked-eye drawing of rhizome: F. flap, R. root, L . leaf, P. petiole, 
L.S. leaf-scar. 
Fig. 2. Adventitiously formed plant. (We owe this drawing to the kindness 
of Mr. T. G. Hill.) 
Fig. 3. Apex of the stem of Botrychium. 
Fig. 4. ,, ,, Helminthostachys : a. stem-apex, /. leaf, l L and / 2 
older leaves with their flaps, f L and f 2 ; f 3 the flaps of a still older leaf. 
Fig. 5. Vascular skeleton : L. leaf-trace, R. root-strand, F.g. foliar gap. 
Fig. 6. Shows the rhizome-stele giving off leaf-trace ( L.T '.) breaking up higher 
into its petiolar bundles : R. root-trace. 
Figs. 7, 8, 8 a. Sections through the petiole just at branching: S.b. sterile 
branches, F.b. sporogenous branch, W. wing of petiole. 
Fig. 9. Median section through stem-apex : Z. leaf, F. flap of older leaf, S. lower 
part of stem, a. apical cell. 
Fig. 10. Apex of another rhizome : a. apical cell, H. hairs. 
Fig. 11. Transverse section of stele and part of cortex : O.E. outer endoderm is, 
I.E. inner endodermis, .S’. T. sieve-tubes. 
Fig. 12. Young part of stele just differentiating : P.X. protoxylem. 
Fig. 13. Longitudinal section of stele : C. cortical parenchyma with pits on the 
walls, E. endodermis, S.T. sieve-tubes. 
Fig. 14. Stele of rhizome, diagrammatic: R. root-strands, L.T. leaf-trace, 
O.E. outer endodermis, l.E. inner endodermis, a discontinuous band. 
Fig. 15. Transverse section through leaf-trace, showing the separation of the 
strand into two halves. 
Fig. 16. Root-apex with damaged apical cell. Segments bulging out. 
Fig. 17. Abnormal forms of tracheids. 
Fig. 18. Transverse section of a leaf- blade. 
Fig. 19. Spiral element (double spirals) J 
Fig. 19. Pitted tracheid (b) ) 
Fig. 20. a.b. sieve-tubes macerated. 
after maceration. 
Photographs. 
Fig. 21. Transverse section of rhizome, root-trace to left, foliar gap above. 
Fig. 22. Transverse section of rhizome after closing of foliar gap. 
Fig. 23. Transverse section of small rhizome showing wood-elements extending 
to centre of stele. 
Fig. 24. Longitudinal apex of stem : a. apical cell. 
Fig. 25. Longitudinal section of sieve-tubes, showing sieve-pits. 
Fig. 26. Transverse section of petiole-bundle. 
Fig. 27. Longitudinal section of root-apex: a. apical cell. 
Fig. 28. Transverse section of root. 
