Roundleaf Greenbriar (Smilax rotundifolia)

4/21/12 Bombay Hook NWR DE boardwalk trail
update 8/31/15: I think this is Roundleaf Greenbriar. I have some pictures on the hard drive somewhere. Will look for them.
Roundleaf Greenbriar

9/19/15 - unknown no longer:
http://www.discoverlife.org/mp/20q?search=Smilax+rotundifolia&guide=Trees&cl=US/NC/Jackson/Balsam_Mountain_Preserve#http://www.cnr.vt.edu/dendro/dendrology/syllabus/srotundifolia.htm

In the background and visible on the right are what may be the flowers of Autumn Olive (Elaeagnus umbellata).