sentences:  These zones provide a useful ultrastructural character for delimiting the classes in Ustilaginomycotina.The host-interactions zones can either be local interaction zones and then characterizing the Exobasidiomycetes, or enlarged interaction zones characterizing the Ustilaginomycetes.Cellular composition
  
  Ustilaginomycotina has a distinctive cell wall composition consistent of mostly glucose and absence of xylose.