ree = e.find('> ul');

                if (subtree.length > 0) {
                    e.addClass('tree-opened');
                    e.removeClass('tree-closed');

                    subtree.slideDown(options.delay);
                    subtree.show(options.delay);

                    subtree.expand(options);
                } 
            });
            return true;
        }

        $.fn.collapse = function(options) {
            options = options || {};
            options.delay = options.delay || 0;
