[R] legend title in effects plot

[Viktor Tron]

Could someone tell how I can change/remove the legend title in a  
(multiline) effect plot?
Thanks
V

In general, how is one supposed to find out answers to such questions?
It is virtually impossible to keep track of what graphical parameters are  
passed on
to which low level function and which don't. Every funciton calls legend  
labels a different
name (title, key, legend.lab, etc.).
I tried the help pages of par,plot,effect,legend, without an effect :-)