The Florida corkwood (Leitneria floridana) is an interesting and rare North American tree. I'm calling it a tree, but sources disagree whether it is a tree or a shrub. Many compromise by calling it a "shrub or small tree."
As you might suspect, the corkwood is a tree with very light wood. In fact, its wood is about 13 pounds per cubic foot, even lighter than cork. In the areas where it grows, it has been often been used for corks and fishing floats by the local residents.
I don't think I've ever seen corkwood, or if I have, I didn't know what it was. If you look at the photos at the USDA Plants database, you'll know as much as I do about its appearance.
I'll suspect that it might be corkwood if I ever happen upon a dense thicket of smooth-barked woody tree-shrubs in the swamp, 12 to 20 feet in height, with long stems, very short branches, and shiny, thick leaves that have reddish stems.
Corkwood is not often seen. "It occurs rarely and locally along tidewater river and in swamps from southeastern Georgia and western Florida to southeastern Texas; and also in parts of Arkansas and Missouri." (from William Carey Grimm's Book of Trees -- see bibliographic info at bottom of the column.)
The Center for Plant Conservation describes the corkwood's range as "scattered ... freshwater swamps, wetland thickets, pond habitats, brackish tidal streams and brackish marshes of coastal southeast Texas, the central Gulf coast of Florida, extreme southeast Missouri, northeast and east-central Arkansas and southwest Georgia."
One might search for the ivory-billed woodpecker in similar places. And, like the ivory-billed woodpecker, corkwood was once far more common in the southeastern U.S. As wetlands have been drained and stream banks bulldozed, corkwood has died out. It is considered a threatened plant in Florida and Texas, and rare in Georgia, Arkansas,and Missouri,
Where the corkwood grows, it is often found in thickets because it spreads by root suckers. It is unusually tolerant of flooding, and it can live in a submerged state for long periods of time. This makes it a valuable tree for controlling erosion along stream banks.
Britton, N.L., and A. Brown. 1913.
An illustrated flora of the northern United States,
Canada and the British Possessions. Vol. 1: 586.
Images of corkwood (Leitneria floridana) on Flickr
Corkwood article in Trees of Georgia