gtk rc file question

[Dave Caswell <davec asylum apocalypse org>]

In the example rc file in the tutorial several of the widget class
lines are listed with leading '*'s, and several aren't: 

      widget_class "GtkWindow" style "window"
      widget_class "GtkDialog" style "window"
      widget_class "GtkFileSelection" style "window"
      widget_class "*Gtk*Scale" style "scale"
      widget_class "*GtkCheckButton*" style "toggle_button"
      widget_class "*GtkRadioButton*" style "toggle_button"
      widget_class "*GtkButton*" style "button"

I was playing around with RC files, and I found that some widget
classes seem to need the * and some don't.  What makes the
difference??

Thanks,
	davec