We read in Exodus 15:22 “And Moses led Israel… from the Red Sea…they went three days in the (desert) and found no water. 23 And when they came to Marah, they could not drink of the waters of Marah, for they were bitter… 24 And the people (complained): ‘What shall we drink?’ 25 And Moses cried to the LORD: and the LORD showed him a tree, and he cast it into the waters, and the waters were sweetened… " What I learned is the Hebrew word 'Aitz' can be translated either as “tree” or a piece of “wood.” What did Moses toss into the brackish waters, turning (healing) bitter into sweet? A piece of wood, or a tree? What kind? Thus... a collection of specimens to be examined.