HEREDITY AND EVOLUTION IN PLANTS 



FIG. 2. Portion of the rhizome of the common brake (Plcris aqnilina) 

 showing a cross-section view at the right. 



Fir.. 3. Cross-section of the rhizome of the bracken fern (Plcris aqul- 

 liiui), showing the tissue systems. Greatly magnified. 



