Oops, I just found my original copy of the song ... I had it all along! Cancel the Lyric Request. I'll see if I can get the song added to the database, as it is unusual and pretty. But, for the record, here are the lyrics I (now) have:

O who art thou, Lady Vangeline,
Thou rulest here like a lovely queen. (2x)
   From the sky thou dost appear
   Bringing blessed water so pure and clear.
O who art thou Lady Vangeline,
Thou rulest here like a lovely queen.

The cypress tree and the lemon tree
Hold up their booughs for a drink from thee. (2x)
   Fail them not, O lovely one,
   Leave them not to burn in the summer sun.
The cypress tree and the lemon tree
Hold up their booughs for a drink from thee.

The water thou bringest from the sky
Must quench their thirst or the trees will die. (2x)
   Mercy, mercy Lady mine!
   Let thy raindrops fall on the tree and vine.
The water thou bringest from the sky
Must quench their thirst or the trees will die.

O who art thou Lady Vangeline,
Thou rulest here like a lovely queen.
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llareggyb, aka Tony Patriarche