horsebrier

n. a very prickly woody vine (Smilax rotundifolia) of eastern U. S. growing in tangled masses having tough round stems with shiny leathery leaves and small greenish flowers followed by clusters of inedible shiny black berries.
Syn. -- bullbrier, greenbrier, catbrier, brier, briar, Smilax rotundifolia. [ WordNet 1.5 ]