This card shows some artist’s renderings of Spanish Moss as it might appear on trees in the Florida area, along with a poem about the putative origins of the plant. As noted in the link above, Spanish Moss is neither a moss nor a lichen, but in fact is a bromeliad.
The description states simply: 252-F — Tropical Florida Series
—The poem is one of several explanations for the existence of the plant.
This postcard was used and is dated28 February 1957.