Concise Bible Dictionary:
The crown placed in derision on the head of the Lord Jesus, when arrayed in a scarlet robe. Though applied to His sacred head by the rough soldiers, it was connived at by Pilate, who presented the Lord in this garb to the Jews, but which only drew forth their cry, “Crucify Him.” We read that the robe was taken off Him, but nothing is said of the crown, so that He may have worn that on the cross. It is supposed to have been made of the Arabian nabk, which has flexible branches with very sharp thorns, and ivy-like leaves: mocking the Lord, as some think, both as a king and as a victor (Matt. 27:2929And when they had platted a crown of thorns, they put it upon his head, and a reed in his right hand: and they bowed the knee before him, and mocked him, saying, Hail, King of the Jews! (Matthew 27:29); Mark 15:1717And they clothed him with purple, and platted a crown of thorns, and put it about his head, (Mark 15:17); John 19:2,52And the soldiers platted a crown of thorns, and put it on his head, and they put on him a purple robe, (John 19:2)
5Then came Jesus forth, wearing the crown of thorns, and the purple robe. And Pilate saith unto them, Behold the man! (John 19:5)).
Nabk – Ziziphus spina-christi