Add Bookmark toolbar icon

I recently upgraded to Safari 6.1 and the toolbar no longer has a + to add bookmarks. I know that you can add bookmarks by going to the Bookmarks dropdown menu and choosing command D. But is there a way to get the plus sign onto the toolbar the way it was in the older version of Safari?

I have tried Customize Toolbar but none of the icon choices are "Add Bookmark." I see New Tab, Home, History, etc. but not "Add Bookmark."

Ideas?

Thank you!