Get data type aliases - Mailing list pgsql-general

I have a function that has an attribute with datatype of character varying. In the pg_type table the oid of the data type points to type varchar

Is there somewhere that identifies the alias for each type?

E.g. 

int4 = integer

varchar = character varying.

 and so on.

I can do an if statement in my code but I'd prefer not to.

Thanks in advance.

Rebecca