i o A USTRALIAJST BO TANY. 



leaves in all ordinary flowering plants (vasculares), are 

 prosenchyma. 



Flowering plants are composed of cellular and vascular 

 tissue combined. 



Between the woody fibres are found spaces filled with 

 air, mostly small, but sometimes forming regular tubes 

 or air passages (lacunae) comparable to chimneys, and 

 are always observable by cutting across any part of a 

 plant. 



Plants composed of cellular tissue alone increase very 

 rapidly in size and number. Several species of the mush- 

 room tribe have been known to multiply to nearly a 

 hundred millions of individuals in a minute. The yeast 

 plant is one of these, a single cell of which is said to be 



t 0V0 P art °f an i ncn acros s. 



The cells of some plants contain crystals of lime and 

 •other salts called raphides, in which case starch, chloro- 

 phyll, oils, sugar, and other granular structures are 

 absent. 



Those cells actively assisting in the vital processes are 



surrounded in higher plants by 

 fibres, winding spirally around 

 definite groups, thus forming ducts 

 for the sap to rise or descend in. 

 Each cell is closed all round, and 

 without any opening. Thus the 

 contents can only get through the 

 cell-wall by a mysterious process 

 of oozing through, termed e?idos- 

 Cellular tissue, showing— a, mose (ingoing) and exosmose (out- 

 a, a, air passages or lacunae, going), produced by forces which, 



