THE SEEDLING AND YOUNG PLANT 65 



spindle-shaped fibres much like the fibres of the 

 wood. 



As a rule, the outer and inner side of these bast 

 groups are in contact with vertical rows of nearly cubical 

 parenchyma cells, strongly thickened on the side next 

 the bast, and each nearly filled with a crystalline clump 

 or with an imperfectly formed crystal of oxalate of 

 lime. Similar vertical rows of crystal cells may also 

 occur within the groups of bast fibres, the walls of the 

 cubical cells being more or less thickened and simply 

 pitted. Occasionally a cell here and there retains thin 

 walls. The vertical rows result from cross- divisions of 

 prosenchymatous mother-cells, the conical ends being 

 found in macerations. 



Within the groups of bast fibres are yet other rows, 

 similarly formed, of parenchyma (fig. 17, l>p), the cells of 

 which are longer, however, attaining the length of the 

 wood-parenchyma ; like the latter also their walls are 

 lignified and rather thick, and they contain starch in 

 the winter. Thus we have parenchyma in the bast. 

 Transitions between these two forms of parenchyma 

 cells are also found. 



The cells of the rays between the bast fibres are 

 thickened and pitted ; they are rounded, and not in 

 vertical series as in the rest of the rays, but are scattered 

 in no particular order. Sometimes they are few, and 

 one or all with very thick walls perforated by pit-canals 

 (fig. 17, to). 



The remaining younger part of the bast consists 



