xy. 



LIST OF Il<LTJSmA.TlOKS, 



Figure 1. 

 (p. 12) 



Figure Z. 

 (p. 14) 



Figure 3, 

 (p. 17) 



Figure 4. 

 (p. 19) 



Figure 5» 

 fp. 23) 



Figure 6. 

 fp. 36) 



Figure 7. 

 (p. S7) 



Figure 8. 

 (p. 29) 



Figure 9. 

 (p. S2). 



Figure 10, 

 (p. 42). 



Urtica diclca . Truncated hair with pe^en- 

 ated tip. (Original) . 



. Zygnema filam,ent « Plasmolysed cells. In 

 hoth cells spirally twisted bodies* 

 (Aftey Kieba). 



Marohantia rhizoids growing through other 

 truncated ones* ^One of the parenchyma 

 cells lying at the base of the trichome 

 is growing out into a compensatory hair, 

 (a) . In b a second, outgrowth. (After Kny) . 



Zea Mays. Half of a cross-section through 

 a root, which had regenerated after split- 

 ting. The cells of the epidermis and exo- 

 dermis are considerably smaller on the 

 side regenerated (the lower side in the 

 figure) than on the original upper Bur:Cace. 

 (After Lopriore) . 



Fagus silvatioa. Cross-sections through _ 

 leaves exposed to varying amounts of light, 

 A, leaf grown in medium intensity. B. typ- 

 ical sun-leaf • C, typical shade-leaf, p, 

 palisade pB»enchyma, sch. spongy parenchyma. 

 1, intercellular spacas. (After Stahl, from 

 Hertwig, , "Zelle und Gewebe") . 



Erigeron canadensis . A, cross-section through 

 a normal stem with richly developed second- 

 ary wood. B, KJross-section through the 

 stem of a greatly dwarfed specimen; the 

 secondary tissues are lacking, p* primary 

 tissues (xylem and phloem) , s, secondary 

 tissues ( of the same) , sk, sclerenchyma. 

 (After Gauchery) , 



Euastrum verrucosum . Cells grovra in sugar 

 sdlution; a, abnormally formed individual; 

 b, dwarf example. (After Klebs) , 



Ficus stipulata . A, part of a cross-section 

 through a sun-leaf; b, through a shade- 

 leaf, (After Stahl) . 



Pinus austriaca . Cross-section through a 

 needle; a, grown in the usual exposure 

 to light f interrupted light)' b, in con- 

 tinuous exposure to electric light, (After 

 Bonnier) . 



Iiunularia , At the left, cross-section 



through a nw|fmally developed thallus (After 

 lestler, Naturl Fflanzenfam, Bd, I, 3, p 17) 

 at the ri^t . cross-section through a spec- 

 imen grown with insufficient light. (After 

 Beauverie) . 



