294 ON THE STEM IN CERTAIN SPECIES OF CARYOPHYLLEÆ AND PLUMBAGINEZÆ. 
EXPLANATION OF THE PLATES. 
Tas. L. 
Acanthophyllum spinosum, C. A. M. 
Fig. 1. Portion of a young leafy shoot. | 
Fig. 2. Transverse section from a young internode: a. cortical parenchyma; b. zone of small and delicate 
cells (cambium region) ; c. wood which abounds in vessels of various calibre ; d. transversely 
lengthened pith-cavity, the cells partly obliterated. 
Fig. 3. a. From a young internode; 6. from the next below; c. from the third—the dividing fissure has 
changed to an opposite direction; d. traces of further lobing become apparent; e. about 4th of 
an inch lower; f. point from which a branchlet is given off. 
Fig. 4. Semi-diagrammatic section from a young shoot of the same, showing the division of the woody 
mass, and a ‘generative zone? surrounding each portion. 
Fig. 5. Transverse section from lower portion of twig, fig. 1. 
Figs. 6 & 7. Sections from older stems. 
Fig. 8. Semi-diagrammatic and enlarged ; the vessels often cut the horizontal plane obliquely. 
Fig. 9. Vertical section showing the vessels obliquely traversing the thin-walled tissue forming the mass 
of the older stems. 
Fig. 10. Diagram from one of the upper branchlets of the twig, fig. 1. In the wood, which is very full 
of vessels—more so, I think, than I have represented—four nearly equal zones are to be counted; 
through these the vessels are irregularly distributed. "The zones are separated by lines of very 
narrow vessels, which, according to my observations, are true spirals. 
Acanthophyllum (sp. dub., Griffiths Affghan Coll. no. 1562). 
Fig. 11. Thin sections, successively removed from an older stem. 
Fig. 12. wu section enlarged : a. cortical parenchyma, with numerous concretions of oxalate of 
e. i 
Fig. 13. Portion more highly magnified, with cords of thickened prosenchyma. 
Figs. 14 & 15. Vertical sections showing * slit-marked” and spiral vessels with prosenchyma. _ 
Fig. 16. Pith, with oxalate of lime. 
Fig. 17. Tangential section dividing a radial parenchymatous cord. 
Ta». LI. 
; Acanthophyllum laxiflorum, Boiss. " 
Fig. 18. Transverse and, fig. 19, vertical sections of the stem. i 
Acanthophyllum (sp. dub., Griffith’s Affghan Coll. no. 1570). 
Fig. 20. Transverse section. Fig. 21. Same more highly magnified. 
Acantholimon diapensioides, Boiss. 
Fig. 22. Transverse section. Fig. 23. Same enlarged. ; 
Acantholimon (sp. A. tomentello aff.). 
vertical sections of portions of the stem. 
Armeria maritima, Willd. 
Fig. 24. Transverse and, fig. 25, 
Fig. 26. Transverse section from lower portion of the stem (passing into the root?). Fig.27. From about jth 
of an inch higher up. Fig. 
j : 28. Section showing numerous radial processes in the same plane. 
1g. 29. Magnified transverse section showing the distribution of the vessels and cords of thick-walled 
prosenchyma. " | 
Fig. 30. Tangential section dividing-a radial cord. 
Fig. 31. Isolated cells from the pith. — 
