I have a vine that has begun appearing around my yard (which is itself rather feral!). It first appeared two to three years ago, and has been slowly appearing in various places around the yard (around 10 sites now). It is easy to remove - if pulled out of the ground it does not resprout.

Here are some images:

The vine, climbing a fence:

http://www.flickr.com/photos/39978310@N00/4551289809/

closeup of an vine ending:

http://www.flickr.com/photos/39978310@N00/4551928556/

underside with seeds/fruit shown:

http://www.flickr.com/photos/39978310@N00/4551929724/

For those who are unfamiliar with Flickr, you can get (much) larger versions of any image by clicking "All Sizes" just above the image.