THE CELLULAR CONSTRUCTION OF THE PLANT 17 



examination show that it is not of uniform texture, like paraffin wax. 

 It is built up of a number of structural units, or cells, of more or less 



FIG. 7. 



External view of the growing point of Hippuris, showing the smooth apical cone 

 bearing alternating whorls of lateral leaves, the youngest nearest to the tip. Magnified. 



cubical form, which are all essentially similar, and are arranged with 

 some degree of regularity (Fig. 8). More highly magnified, they are seen 

 to be all separated from one another by definite, but very thin cell-walls 



FIG. 8. 



Median longitudinal section of the apex of a quite young bud of Hippuris. 

 =epidermis. />c=periblem. />/=plerome. After De Bary. (xsoo.) 



(Fig. 9). Each unit comprises a granular mass of material, colourless 

 and semifluid in the living state, which is the cytoplasm. In a central 



B.B. B 



