'Tamarisk tree' in the Bible

Abraham planted a tamarisk tree at Beersheba, and there he called on the name of the Lord [in prayer], the Eternal God.

But Saul heard that David and the men who were with him had been discovered. Now Saul was in Gibeah, sitting under the tamarisk tree on the high place with his spear in his hand, and all his servants were standing around him.