MICROSCOPIC STRUCTURE OF PHANEROGAMIC PLANTS. 



355 



< gelatinous ' layer that intervenes between the cells of the Algee ( 229). 

 This, in an early stage of their development, is often very abundant, oc- 

 cupying more space than the cells themselves, as is seen in Fig. 239, A; 

 and the cell-cavities are not separated from it by the interposition of a 

 distinct membrane. As the cells enlarge and increase by duplicative sub- 



Sections of Cellular Parenchyma of Aralia, or Rice-papeF plant: A, transversely to the axis 

 of the stem; B, in the direction of the axis. 



division (B), the intervening substance diminishes in relative amount; and 

 as the cells advance towards their mature condition (c), it merely shows 

 itself as a thin layer between them. There are many forms of fully 

 developed cellular parenchyma, in which, in consequence of the loose 

 aggregation of their component cells, these may be readily isolated, so as 



Ficr. 237. 



Section of Cellular parenchyma 

 of Rush. 



Cubical parenchyma, with stellate 

 cells, from petiole of Nuphar lutea. 



to be prepared for separate examination without the use of re-agents 

 which alter their condition: this is the case with the pulp of ripe fruits, 

 such as the Strawberry or Currant (the Snowberry is a particularly 

 favorable subject for this kind of examination), and with the parenchyma- 

 of many fleshy leaves, such as those of the Carnation (DiantJms caryo- 



