These are quiet, majestic giants in the swamp, sharing their space with towering cypress and the mournful hoot-owls. Their trunks are flared out at the base (much like cypress), and of course you've probably seen their peculiar, crooked roots arising from the wet ground, together with knobby, upright knees of the cypress. Mosses and liverworts frequently cover their thin, scaly bark. After a flood event, water lines can be seen on them.
I remember as a kid floating around in a boat in a spooky swamp with my dad, who explained that the lines distinct and clear, way up on the trunk were from floods. (It was amazing to me. Then I caught a mudfish.) These trunks, especially on the larger trees, are sometimes hollow, and if there is a convenient knot-hole or crack, will provide perfect habitat for resident bats and other critters.
Large trees really do look a good bit like cypresses nd have been source of confusion to hikers (and beginning botanists). It’s actually rather easy to tell the difference. The bark of this tree will be gray and fairly smooth, sometimes with checkering and various kinds of mosses like to grow on the bark. The base of the tree is swollen.
Cypress, on the other hand, has bark which is a bit shreddy toward the base and has a sort of orange tint. Mosses don’t seem to grow as commonly on cypress. Cypress tree bases are also swollen, but in addition, are commonly fluted, or buttressed around the edges, especially on the larger individuals.
Our mystery tree occurs naturally only on the coastal plain, from southern Virginia through the Florida panhandle, over to eastern Texas and up the Mississippi River Valley as far as southern Illinois. It really likes its feet wet, and is at home in deep river swamps, easily capable of surviving long periods of flooding.
Its leaves are elliptical, up to 8 inches long and often with a large tooth (or two) on the margins. Now, in the early autumn, the leaves start to turn a rich, deep gold-yellow before falling away. The sour, one-seeded fruits, which are shaped like large, narrow olives, are ripening now. They are tasty if you can find one without too many bug holes. During some years, huge amounts of these fruits will be produced, eventually falling away, and providing a food source for wildlife. If you are in a quiet swamp with these plants, you can hear the fruits falling: “ka-PLOOP.” Seeds distributed this way commonly fall to the bottom of a swampy gut, and eventually sprout, but not until the swamp enters a dry period.
The plants bloom in the late spring, producing masses of flower clusters up in the canopy. These flowers are much prized by bees for their nectar. In fact, bee-keepers have learned that an excellent honey can be made from this nectar. The trick is to move your bee-hives into the swamp at just the right time, when not many other species are blooming; otherwise the honey would be something of a mixture of flavors.
[Answer: "Water tupelo," Nyssa aquatica]