[eluser]mddd[/eluser]
@ecotypes: As far as I can see, what you are doing is correct. A url like /plants/pindex/alpha/a should just work! Assuming you have a controller called Plants in you controllers folder, and that controller has a method (=function) called pindex. Anything after that should not give you a problem. It is okay to have extra information after the controller/method. A 404 error means that CodeIgniter could not find the controller with that name (Plants) or you have no method in that controller with the right name (pindex). Do you have any folders INSIDE your controllers folder? If you had a folder called Plants in there, that WOULD be a problem. Because CI can work with one level of folders INSIDE the controllers-folder. In that case, it would look for a controller called 'pindex' inside the 'plants' folder in your controllers-folder..
@umefarooq: I don't see that that makes a difference. You would be rewriting an address into exactly the same address. No change.
