

So6 BOTANICAL GAZETTE [october 



3 



EXPLANATION OF PLATES XXVII-XXX 



PLATE XXVII 



Fig. i. — Cross-section of normal shoot showing topography: a, integu- 

 mentary region; b, palisade region; c, mucilage mass at peripheral side of 

 vascular bundle; d y stelar region; Xo. 5. 



Fig.. 2. — Cross-section of etiolated-greened shoot showing topography: 

 a, epidermis; b, cortex; c, leaf trace; d, vascular bundle; e, stele; X12. 



Fig. 3. — Cross-section of etiolated shoot showing topography; same 

 ettering as fig. 2; X12. 



Fig. 4. — Epidermis from normal shoot after removal of cuticle; X395. 



Fig. 5. — Epidermis from basal region of etiolated shoot ; X395. 



Fig. 6. — Epidermis from apical region of etiolated shoot; papillae not yet 

 fully developed; X395. 



Figs. 7-10. — Normal development of stoma in epidermis of etiolated 

 shoot; fig. 8 is vertical section of stage shown in fig. 7; X525. 



PLATE XXVIII 



Fig. 11. — Part of transverse section through outer region of normal shoot: 

 a, epidermis with layer of cuticle above; b, hypoderm; c, palisade region; 

 first layer of hypoderm is a crystal-containing sheet; 2 air chambers shown; X85. 



Fig. 12. — Part of transverse section through etiolated-greened shoot 

 reaching from epidermis into stele; palisade tissue has appeared; round 

 bodies represent chloroplasts ; a and c as in fig. n; d, inner spongy cortex; 

 X85. 



Fig. 13. — Part of transverse section of etiolated shoot reaching from 

 epidermis into stele; papilla shown in upper right-hand corner and part of 

 mucilage mass in lower left-hand corner; black dots represent leucoplasts, 

 and circles represent starch grains; X85. 



Fig. 14. — Detail of integumentary region of normal shoot: lettering as 

 in fig. 11; X525. 



Fig. 15. — Part of transverse section of etiolated shoot shortly after 

 removal to light; decortication of outer layers of shoot involving a stoma in 

 progress; a, future surface wall of new epidermis; X525. 



Fig. 16.— Detail of stage of adjustment of etiolated-greened shoot shown 

 in fig. 12; remains of dead cell showing below, projecting into air space; X525. 



Fig. 17. — Detail of transverse section shown in fig. 13; reticulate bodies 

 are nuclei; irregular bodies are chloroplasts and leucoplasts; large, round, 

 lightly stippled bodies are grains of storage starch; X525. 



PLATE XXIX 



Figs. 18-25. — Development of papilla as seen in transverse sections of 

 etiolated shoot : a, inner wall of initial cell; b, first transverse wall; c, stoma; 

 fig. 19, X390; figs. 20, 22, X245; all others, X525. 



Fig. 26.— Vertical section of young papilla cut parallel with long axis of 

 etiolated shoot, showing side view of guard cell; X525. 



