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METHODS IN PLANT HISTOLOGY 



Beautiful mounts of the peristome are easily and quickly made. 

 Take a capsule at the stage when the operculum is just ready to fall off, 

 or has just fallen off; with a sharp razor cut off the end of the capsule 

 just below the line of the annulus; put it into absolute alcohol for an 

 hour, change the alcohol, clear in clove oil, transfer to xylol, and mount 



Fig. 88. — Mnium: upper part of capsule showing two teeth of the peristome cut longitudinally. 

 Fixed in formalin alcohol and stained in safranin and light green. X 120. 



in balsam. Cut some off without removing the operculum. The views 

 will not be quite as clear, but the perfect regularity of the teeth will 

 not be disturbed. No staining is either necessary or desirable (Fig. 

 89). If some are mounted one side up, and some the other, it will 

 make the preparation more instructive. 



The mature sporophytes of Sphagnum are exceptionally hard to cut. 

 It will be worth while to prick the capsule with a needle when the 



