christ's-thorn

from The Century Dictionary.

• noun The Paliurus aculeatus, a deciduous shrub, a native of Palestine and the south of Europe: so named from a belief that the crown of thorns placed upon the head of Christ was made of it. See Paliurus.

from the GNU version of the Collaborative International Dictionary of English.

• noun (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.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun spiny tree having dark red edible fruits
• noun thorny Eurasian shrub with dry woody winged fruit