The Original Mystery Plant
Photo by Linda Lee

Many people are choosing to live and vacation near the coast. The surf, the sand, the sun and the wonderful breeze have always been an attraction. Residents along the coasts must constantly be vigilant and pay close attention to the weather.

Fortunately, sophisticated weather analyses provide enough of a warning before hurricanes hit, which allows for evacuation; however, the plants growing at the beach can't throw everything into the car and board up the windows.

Plants growing in maritime ecosystems, must put up with a variety of challenges. Vegetation along the coastline must be able to withstand deep sandy substrates, high winds, and its resultant salt and sand spray.

Students studying natural history will recognize a wide variety of strategies within plants that allows them to grow, and indeed, flourish in such challenging places.

The mystery plant is a little beach bum that really has sand in its shoes. It is widely distributed along the Atlantic and Gulf coasts from New Jersey to Louisiana. It's a resident of back dunes and sandy swales just inland from the beach, sometimes appearing on the tops of the fore dunes.

It is a wiry herb, usually sprawling stiffly on the ground and forming a twiggy mat. The leaves are hairy and almost shaggy with a layer of soft, grayish hairs. This layer of hairs acts as a kind of sunscreen. Although plants don't get sunburned like we do, they definitely can be injured by too much bright sun.

The flowers sport four sepals and four golden, yellow petals. There are eight stamens and a single pistil divided toward the end of the style into four threadlike stigmatic branches. The flower parts are fused to the point that they form a narrow tube or cup at the top of the ovary. The matured ovary is long and skinny, which will eventually pop open and spill its numerous seeds onto the sand.

This species has about 70 cousins in North America in the same genus, and they all belong to the evening primrose family of plants, or Onagraceae.

The family is fascinating in a number of ways. For instance, many of its constituent members have light, brightly- colored flowers that are open at night, often attracting moths. The Mystery Plant will have its flowers wide open in the middle of the night on the dunes and will remain open the next day until about noon and then the petals turn a pink, salmon color, and shrivel up.

Answer to this week's mystery plant

[Answer: "Seabeach evening primrose," Oenothera humifusa]

Dr. John Nelson is the curator of the USC Herbarium.

To learn more about the Herbarium, call 777-8196. The

department also offers free plant identification.

www.herbarium.org