Any of many plants with thorny stems growing in dense clusters, such as many in the Rosa, Rubus, and Smilax genera.
User Defined Definitions
"tangled mass of prickly plants"
"a thorny stem or twig"
"Eurasian rose with prickly stems and fragrant leaves and bright pink flowers followed by scarlet hips"
"a very prickly woody vine of the eastern United States growing in tangled masses having tough round stems with shiny leathery leaves and small greenish flowers followed by clusters of inedible shiny b"
"evergreen treelike Mediterranean shrub having fragrant white flowers in large terminal panicles and hard woody roots used to make tobacco pipes"