14 LANG, Morphology of the Stock of Isoetes lacustris. 



groove. Since such sections bring other features of im- 

 portance into prominence they must be briefly described. 

 Sections in the plane of the lobe will obviously cut 



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l'h<- 3- —Outlines of four longitudinal sections in the plane of the 

 lobes through a large stock of Isoetes lacustris. 

 Description in the Text. 



the root-bearing extension of the stele at right angles to 

 the growing edge. Four sections from a longitudinal 



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