*christ's-thorn*

n. (Bot.) One of several prickly or thorny shrubs found in Palestine, especially the Paliurus aculeatus, Zizyphus Spina-Christi, and Zizyphus vulgaris. The last bears the fruit called jujube, and may be considered to have been the most readily obtainable for the Crown of Thorns. [ 1913 Webster ]