METABOLIC CHANGES 



825 



no definite position. In other cases, however, its position is 

 fixed." 



I will cite a few especially instructive examples from the 

 numerous observations, on which Haberlandt has based his laws. 



The epidermal cells of many plants often exhibit thickenings 

 on the surface of their walls ; this may occur either on those 

 pointing outwards or on those pointing inwards. The nucleus 

 here lies near to the one in which the thickening occurs, being 

 always close to the middle of the latter. The examples given in 

 Fig. 161 show this very distinctly: No. I., a row of cells from the 

 epidermis of a foliage-leaf of Cypripedium insigne ; No. III. an 

 epidermal cell of the fruit-scale of Carex A B 



panicea, and No. IV. a young epidermal celi 

 of a foliage-leaf of Aloe verrucosa. 



A second series of investigations have 

 been made upon the development of plant- 

 hairs, growing both above and below 

 ground. 



Ill 



IV 



FIG. 161. FIG. 162. 



FIG. 161. I Epidormal cells of a foliage leaf of Cypripedium insigne (after Haberlandt, 

 PI. I.. Fig. 1). II Epidermal cells of Luzula maxima (after Haberlandt, PI. I., Fig. 3). Ill 

 Epidermal cells of the fruit-scale of Carex panicea (after Haberlandt, PI. I., Fig. 14). IV 

 Young epidermal cells of a foliage leaf of AloS verrucosa (after Haberlandt, PI. I., Fig. 7). 



FIG. 162. A Root-hair of CannaUs sativa (after Haberlandt, PI. II., Fig. 26). B Forma- 

 tion of root-hairs of Pt'sitm sativum, (after Haberlandt, PI. II., Fig. 22). 



