Britton and Taylor: Life History of Schizaea pusilla 19 



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



78. Cross-section of root. a f thickened inner walls of cells of the ground tissue 

 next to endodermis (b) ; c, phloem; d 9 xylem, X 292^. 



79. Showing rhizome with four leaves and five roots ; a, rhizome ; b, roots ; c> tri- 

 chomas (the intemode here represented is unusually long and distinct), X 8- 



80. Cross-section of rhizome not far from tip, X I2 °- a , cells filled with starch ; 

 b, endodermis ; c, phloem ; d, xylem ; e, fungus hyphae entering epidermal cells. 



Plate 6 



81. Surface view of dorsal side of sterile leaf, showing the two rows of stomata 

 with the glands alternating with them, X l 2 °- 



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

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

 (d) between the epidermal cells, and the way the guard cells (<?) rest on epidermis at 



€ % X 2IO. 



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



84. Longitudinal section of same, a, epidermal cells ; b ) one guard cell of stoma ; 

 r, 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 ; d, 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 r, guard cells. 



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

 a, bundle ; b t endodermis, X 45- 



88. Bundle from sterile leaf, a, endodermis; c, phloem; d, xylem, X 2I °- 



89. Mesophyll tissue from sterile leaf, X 2I °- 



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, ^ 210. a t stoma; b f air space. 



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



2IO. 



94. Cross-section of bundle in sporophyll, marking as in Figs. 88, 90, X 2 I°- 



