diff --git a/includes/form.inc b/includes/form.inc
index ea9afbe1523..63c322abdbc 100644
--- a/includes/form.inc
+++ b/includes/form.inc
@@ -3031,7 +3031,7 @@ function form_process_radios($element) {
  *   An associative array containing:
  *   - element: An associative array containing the properties of the element.
  *     Properties used: #title, #value, #return_value, #description, #required,
- *     #attributes.
+ *     #attributes, #checked.
  *
  * @ingroup themeable
  */