diff --git a/themes/engines/phptemplate/phptemplate.engine b/themes/engines/phptemplate/phptemplate.engine
index 2205801acd6ee8fc91b6ce224b4b4ebf67462534..5a3dc48b36486063163849137a08141dbd547bf7 100644
--- a/themes/engines/phptemplate/phptemplate.engine
+++ b/themes/engines/phptemplate/phptemplate.engine
@@ -372,7 +372,10 @@ function phptemplate_box($title, $content, $region = 'main') {
  * @param $variables
  *   A sequential array of variables passed to the theme function.
  * @param $suggestions
- *   An array of suggested template files to use.
+ *   An array of suggested template files to use. This may include a path when
+ *   the suggested template is contained within a sub-directory of the theme.
+ *   They are set from _phptemplate_variables() or the theming hook invoking
+ *   _phptemplate_callback().
  */
 function _phptemplate_default($hook, $variables, $suggestions = array(), $extension = '.tpl.php') {
   global $theme_engine;