[R] Listing factor levels for elements of letters in an rpart plot

[Cliff Behrens]

I would like to create a list of factor levels represented by elements 
of letters shown in an rpart plot.  It seems that the order of levels 
for a factor are different than the alphabetized order returned a simple 
list command, e.g., rpartModel$factor_name. 

I was also wondering how best to model factors with many levels, or does 
the classification algorithm already subset these?  I was thinking of 
thresholding observations on some minimum count for each level.