365 Urban Species. #332: American sea rocket
Photo by urbpan. Location: Revere Beach
Urban species #332: American sea rocket Cakile edulenta
If we had come across this plant while it was flowering, identification would have been easy. As it was, fleshy and succulent, it resembled a cactus relative. But that's merely an adaptation for retaining water while living on the bare salty sand above the high water mark. Many different unrelated plants, including glasswort or pickleweed (Salicornia) or Europe and North America as well as the several species commonly known as ice plant, from South Africa, have this characteristic. If the flowers were present, they would have been cross-shaped, with four small petals. Readers who have been following along since spring recognize this as a hallmark of the mustard family, a group of mostly Eurasian weeds that grow fast and grow early. American sea rocket is a native mustard plant, though there is a European variety Cakile maritima which is replacing the native plant in some locations. Once a plant has adapted to the harsh conditions of the beach, a city springing up around it may not be a problem. American sea rocket is known to grow in Boston, New York City, Los Angeles, and even on the considerably less salty shores of Chicago. It has also been detected in Australia, but it is not yet considered a problem there.
Earlier in the year, lavender cross-shaped flowers were growing at these sites on the plant.
Thanks to pycnanthemum for the identification.