Form Types can be represented with a tree. Some types inherits each other and all form types inherits thefield type (as of Symfony 2.0,form in 2.1).

We currently have aInherit options section in each reference article with some relevant inherit options. In order to keep this up to date, someone needs to:

• Recheck every parent/child relation (is it correct? is there a link?)
• Recheck the inherit options. Are they relevant? Are their other relevant
  options that should get placed here?
• Add a list of links to the description of some options which are not
  relevant enough to get documented on this page. This to avoid long
  articles.

A 'tree' of all parent/child relations (in 2.0) and their options can be found inthis gist.