-!Ub INDEX. 



U 



Ulmio acid, as a bye-product of metabolism, 159. 

 Unicellular plants, 2, 96. 

 Urtica, Stinging hairs of, 33, 34. 



Vacuoles, in cytoplasm, 7, 15 ; Origin of, 21 ; Contents of,-iij. 

 Vallisneria, Assimilating cells of, 13 ; Starch-formation in ohloroplasts of, 



17, 18 ; Plasmolysis in, 16, 17 ; Rotation of protoplasm in, 15. 

 Variation, Movements of, 185. 

 Vascular bundles, Origiu of, 50, 51, 52 ; Arrangement of, in Dicotyledons, 



50 ; in Jlonocotyledons, 52. 

 Vascular cryptogams. Position of, 6. 

 Vaucheria, Structure of, 93 ; Swarmspores of, 95 ; Sexual reproduction in, 



95, 151 ; Plasmolysis in, 95 ; Rotation of protoplasm in, 95 ; Encysted 



spore of, 95, 153. 

 Vegetative cell, in microspore, 121, 132. 

 Vegetative propagation, see QemmcB, Soredia. 

 Ventral canal-cell, see Canal-cells. 

 Vessels, Formation of, 65 ; Reticulate, 66 ; Pitted, 65, 66 ; Annular, 69 ; 



Scalariform, 66 ; Function of, 71. 

 VitaUty, Conditions favouring, in cytoplasm, 12, 156. 

 Volvocineae. see Sphmrella. " 



W 



Waller, Prof., Experiments of, in connection with germination of seeds, 11. 



Water, Absorption of, 172, 173, 189 ; Importance of, to the cell, 10, 12 ; 

 of constitution, 10 ; Evaporation of, from leaves, 28, 174 ; Conduction 

 of, 71, 174, 175, 176, 177 ; AssimUation of, 18, 157, 159, 167, 180 ; 

 in cell-sap, 17, 171. 



Wax, Occurrence and formation of, in plants, 172. 



Wood, see Xylem. 



Wood-parenohyma, 70. 



Xakthophyll, see Phylloxanthin. 



Xylem, Origin of first elements of, in bud, 50, 79 ; Origiu of, from cambium, 



49, 52, 65; Details of, 65, et seq. ; Functions of, 71, 175; of open 



bundles, 53 ; of closed bundles, 52. 



