This one is for the fiddler crabs, sandpipers, snails and everybody else who loves the salt marsh. It's a plant of open salt flats or meadows landward of the beach, places that tend to be frequently flooded by salt water during high tide, and then drained away when the tide goes out. These sorts of places are fascinating biologically, and there are plenty of natural history stories here to be investigated.

Our plant is technically a small shrub, and it is a bit woody, at least on larger individuals. The smooth stems tend to be upright as well as sprawling, and they come up from buried rhizomes. There are no real leaves to look at, and the whole plant is usually bright green. (Sometimes they turn a bit red.) This plant features "succulence" as a survival feature, and it stores plenty of water in its tissues.

If you take a close look at a fresh plant, you'll see a rather pronounced segmented look to the stems. The segments represent nodes up and down the stem, and the intervening internodes are a bit swollen and fleshy; sometimes a stem will have a kind of beaded appearance. There are no real leaves to see, only scale-like places at each node. The nodes are opposite each other. At the upper end of a given node, three very tiny flowers will be buried within the tissue, just barely visible when they open up. The plants' tissues are not only good at storing water, they contain a considerable amount of salt, which shouldn't be a big surprise, considering its habitat. (Plants adapted to habitats containing high concentrations of salt, whether at the coast or farther inland, are termed "halophytes," and they generally feature complicated physiologies enabling them to endure life in a salty place.)

It seems that growing on a tidal salt flat is a very harsh environment for all the residents involved. Interestingly, our Mystery Plant usually has as its neighbors a variety of unrelated species that have adopted a similar "look." Presumably, all of these unrelated species have keyed into a very successful suite of strategies for dealing with their surroundings. This species is fairly common from New England all the way to Mexico, and it also occurs along much of the California coastline.

Our little marsh friend is edible, belonging to the same plant family (Chenopodiaceae) that gives us spinach and beets. Next time you go crabbing at low tide along a tidal creek, be on the lookout. Watch out for the mud, of course, and the oyster shells out there… (Photo by Linda Lee.)

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John Nelson is the curator of the Herbarium at the University of South Carolina, in the department of biological sciences. As a public service, the herbarium offers free plant identifications. For more information, visit www.herbarium.org or call 803-777-8196.