Brittun AM) Tavi-or : Life Historv of Schizaea pusilla 19 



77. Root-cap ; here shown in five series. 



78. Cross-section of root. </, thickened inner walls of cells of the ground tissue 

 next to endodermis (A) ; c, phloem ; </, xyleni, X 292^2. 



79. Showing rhizome with four leaves and five roots ; <r, rhizome ; /', roots ; c, tri- 

 chomes (the internode here represented is unusually long and distinct), > 8- 



80. Cross-section of rhizome not far from tip, X 120. ir, cells tilled with starch ; 

 d, endodermis ; r, phloem ; ,/, xylem ; e, fungus hyphae entering epidermal cells. 



Plate 6 



81. Surface view t)f dorsal side of sterile leaf, showing the two rows of stoniata 

 with the glands alternating with them, X 120. 



82. Portion of epidermis of sterile leaf with three stomata, a, b, c. a, shows the 

 chlorophyl grains ; in /' the contents have been removed to show the original cross-wall 

 ((/) between the epidermal cells, and the way the guard cells {e) rest on epidermis at 



f, X 210. 



83. Oblique view of sterile frond showing raised stomata (<;). 



84. Longitudinal section of same. </, epidermal cells ; /', one guard cell of stoma ; 

 c, air cavity. 



85. Cross-section of same, a, guard cells ; b, air cavity, X 210. 



86. Five diagrams showing development of stoma. I b, cross-wall between epi- 

 dermal cells ; 2 /', mother cell of stoma with U-shaped wall ; c, formation of longi- 

 tudinal wall through mother cell dividing it into the two guard cells ; </, shows curve in 

 original cross-wall, and the splitting of the longitudinal wall. The dotted line indi- 

 cates the relative size of the guard cells which have started to swell. In c, the stoma is 

 complete ; i c, original cross-wall ; 2 c, guard cells. 



87. Diagram of cross-section of sterile leaf showing the two rows of stomata (t). 

 a, bundle ; b, endodermis, X 45- 



88. Bundle from sterile leaf, a, endodermis; c, phloem; d, xylem, X 210. 



89. Mesophyll tissue from sterile leaf, X 210. 



90. Cross-section of a young sterile leaf with a rudimentary bundle, marking as 

 in Fig. 88, X 210. 



91. Diagram of cross-section of fertile leaf, marking as in Fig. 87, X 45- 



92. Stoma seen in cross-section of sporophyll, X 210. «, stoma ; b^ air space. 



93. Two epidermal cells from cross-section of sporophyll showing warts («), X 

 210. 



94. Cross-section of bundle in sporophyll, marking as in Figs. 88, 90, X 210. 



