form_for problem with singular resource

Can you use polymorphic urls with form_for when you have a singular
resource?

In routes.rb
  map.resource :blog

In BlogsController
  def new
     @blog = Blog.new
  end

In new.html.erb
  <% form_for @blog do |f| %>
  ....
  <% end %>

But the view is giving me the following error.

undefined method `blogs_path' for #<ActionView::Base:0xb691281c>

I do not know why @blog is converting into blogs_path. Shouldn't it be
converted to create_blog_path since @blog is a new record? If it was an
existing record I would assume it would go to update_blog_path or
something.

Can someone please explain what I am doing wrong.