24 
PEOEESSOE W. C. WILLIAMSON ON THE OEGANIZATION 
Plate 1. fig. 12. A spiral vessel from the specimen fig. 8. Enlarged 400 diameters. 
Plate 3. fig. 13. Transverse sections of portions of two vessels ( d ) of the vascular bundle 
of a petiole, exhibiting part of the bundle-sheath at e and a detached 
fibrous bundle at f. Enlarged 350 diameters. 
„ fig. 14. Transverse section of a vascular bundle from fig. 1, with enlarged gum- 
canal ( c ) and cellular bundle-sheath ( e ). Magnified 65 diameters. 
„ fig. 15. Longitudinal tangential section of the cortical layer of a young rachis, 
with alternating bands of prosenchyma (b) and parenchyma (a). 
Enlarged 65 diameters. 
Plate 2. fig. 16. Part of the hypodermal layer of the transverse section (fig. 1), showing 
the wedge-shaped bands of prosenchyma (6) projecting into the 
parenchymatous tissue, a. Enlarged 80 diameters. 
Plate 4. fig. 17. A similar section to fig. 16, from Capt. Aitken’s specimen, showing 
the detached islets of hypodermic prosenchyma ( b b") and gum- 
canals at c , c. 
Psaronius Benaultii. 
Plate 3. fig. 18. Transverse section of a cluster of rootlets. Natural size. 
Plate 4. fig. 19. Transverse section of the superficial cortical parenchyma of a stem, 
with the adventitious rootlets passing outwards through it. Enlarged 
12 diameters. 
Plate 3. fig. 20. Cluster of free rootlets, exhibiting numerous radicular epidermal hairs. 
Enlarged 12 diameters. 
„ fig. 21. Portions of three rootlets, with their radicular hairs. Enlarged 40 dia- 
meters. 
Plate 4. fig. 22. Central vascular bundle of a compressed rootlet, imbedded in condensed 
cellular tissue. 
,, fig. 22*. Transverse section of a specimen from Mr. Carruthers’s cabinet, 
exhibiting a vascular bundle ( d ) of the stem enclosed in parenchyma. 
Natural size. 
„ fig. 22**. The lower part of fig. 22*. Enlarged 8 diameters. 
Kaloxylon HooJceri. 
Plate 5. fig. 23. Transverse section of a matured stem. Enlarged 29 diameters. 
„ fig. 24. Transverse section of a very young stem or branch, with the central 
vascular axis, but with no exogenous growths. Enlarged 24 diameters. 
„ fig. 25. Similar section to fig. 24. Enlarged 24 diameters. 
„ fig. 26. Obliquely transverse section of a matured stem deprived of its outer 
bark. Enlarged 36 diameters. 
„ fig. 27. Tangential section of a vascular exogenous wedge made near its peri- 
pheral extremity, and showing the vertical medullary rays at/*,/. 
Enlarged 60 diameters. 
