I'm looking for some songs that have a line similar to "In the middle of the ocean there grows a tall tree" so I might get some backround & maybe some histories, dates & origins of this expression.

Old Paint:
In the middle of the ocean there grows a tall tree
I'll never prove false to the gal that loves

Flash Company:
In the middle of the ocean there shall grow a myrtle tree
If ever I prove false, my love, to the girl that loves me.

American Stranger/I'm a Stranger in This Land:
In the middle/midst of the ocean shall spring a myrtle/maypole tree
If ever I prove unfaithful/false to the girl that loves me

It's a bit like the song The Lambs on the Green Hills

The lambs on the green hills, they sport and they play
And many strawberries grow round the salt sea
How sad is my heart when my love is away
How many's the ships sails the ocean

The above is a little rational the below False Bride

The ladies and gentlemen asked o' me
How many black berries grow roon the salt sea
I gade aen back with a tear in my e'e
How many ships sail in the forest.

Yup I know, showing impossibilities, right & it being used with a bit of poetic license. At least in with the above 2 songs (The Lambs on the Green Hills & The False Bride) there's one song that seems to have a bit more rational than the other. I'm wondering if anyone has any other info on another song that might not have such or as much riddling (hum, Riddling?)? Or is it as simple to "the folk" as a "on a cold day in hell"?
Thanks
Barry