472 
PROFESSOR W. C. WILLIAMSON" ON THE ORGANIZATION 
PLATE 31. 
Fig. 4. Vertical section of a stem passing obliquely through the outer cortical 
parenchyma at its upper end, and through the centre of the medulla at its 
lower one. Enlarged 40 diameters, a. Medullary cells, b. Vascular zone. 
c. Innermost cortex, cl, cl'. Radiating laminae, cl". Lacunae, e. Outer 
cortical parenchyma. Messrs. Cash and Hick. 
PLATE 30. 
Fig. 5. Transverse section. Enlarged 55 diameters. a. Central axis, chiefly or 
wholly composed of vessels, b. Exogenous zone. c. Inner cortex, d. Radia¬ 
ting laminae, cl". Lacunae, e. Outermost cortex, f. Vascular bundle go ing 
off to some lateral appendage. Mr. Spencer. 
PLATE 28. 
Fig. 6. Transverse section of a stem, enlarged 55 diameters, but having a much thicker 
outer cortex. References as in fig. 5. Mr. Spencer. 
PLATE 29. 
Fig. 7. Section through a branching structure. Enlarged 55 diameters. At A is an 
obliquely transverse section through a branch, a. Central axis composed of 
a cluster of cells and vessels, c. Delicate elongated cells of the inner bark. 
d. Radiating laminae, cl". Lacunae, e. Outer cortical parenchyma. At B 
is an almost longitudinal section through a dichotomising branch. Refer- 
ences as at A. At C is a small vascular bundle, a", passing outwards. 
Mr. Spencer. 
PLATE 28. 
Fig. 8. Form of vascular tissue. Enlarged 267 diameters. 
Fig. 9. Form of vascular tissue. Enlarged 267 diameters. 
PLATE 29. 
Fig. 10. Form of vascular tissue. Enlarged 267 diameters. 
Fig. 11. Form of vascular tissue. Enlarged 524 diameters. 
Fig. 12. Form of vascular tissue. Enlarged 267 diameters. 
Fig. 13. Form of vascular tissue. Enlarged 267 diameters. 
o o 
