What was the Crown of Thorn in the Lord's Passion made of?

In Matthew 27:29 we read: "..and after twisting some thorns into a crown, they put it on his head. They put a reed in his right hand and knelt before him and mocked him, saying, “Hail, King of the Jews!” I wish to know the name of the plant or the tree, the thorns of which were used by the soldiers to make the crown. Has the Catholic Church made some research into the nature and properties of the thorns?