List of Plates 



Electron micrograph of the outermost lamellae in the wall of Valonia 



ventricosa. Pd-Au shadowed; magnification 25,000 x Frontispiece 



PLATE I 

 Fig. 1. The structure of the stem of an Angiosperm as figured 

 by Grew (1682) 



PLATE 



Fig. 1 



II 



m 



Fig. 2 



Diagrammatic representation of the method used 

 obtaining X-ray diagrams of fibrous material 



(a) X-ray diagram of wood from the 20th annual ring in 



a stem of Picca abies 



(b) Chart corresponding to Fig. 2{d), showing the indices 



of the planes which give rise to the various arcs 

 Fig. 3. X-ray diagram of hemp fibres before and after delignifi- 

 cation 



facing page 

 4 



42 



43 

 42 



PLATE III 



Fig. 1. The first order in Newton's colour series as shown by a 

 quartz wedge 



Fig. 2. The appearance of starch grains between crossed Nicols 

 over a plate, Red 1 



Fig. 3. The appearance of bordered pits in conifer tracheids under 

 conditions as in Fig. 2 



Fig. 4. A piece of Valonia cell wall under the polarizing micro- 

 scope between crossed Nicols 



PLATE IV 



Fig. 1 . Typical X-ray diagram of a single piece of Valonia wall, 

 beam perpendicular to the surface 



Fig. 2. X-ray diagram of the Valonia wall at a "pole" of its 



structure 

 Fig. 3. Model representing the wall structure of a Valonia vesicle 



Fig. 4. X-ray diagram of a bundle of parallel filaments of 

 Cladophera sp., beam perpendicular to filament length, 

 CuKa radiation 



between pp. 

 64 and 65 



facing page 

 104 



104 

 105 



105 



PLATE V 



Fig. 1 . Comparison of the X-ray diagrams of Cladophora cultured 

 under constant illumination and under normal light- 

 dark alternations 



Fig. 2. X-ray diagram of a bundle of parallel cells of Hydrodictyon 



Fig. 3. Transverse section of tracheids in Pinus radiata between 

 crossed Nicols 



112 

 112 



113 



PLATE VI 



Figs. 1-7. X-ray diagrams of spirals constructed using filaments between pp. 

 of well-oriented artificial silk 128 and 129 



XI 



