Marsh Sandwort (Arenaria paludicola)
Listing Status: Endangered
Flowering from May through August the marsh sandwort has a petite and fetching flower. The flowering shoots, which produce small, solitary, white flowers, often ascend among the leaves and stems of other marsh plants like rushes and sedges. Each flower produces a few, small, black seeds, but the type of potential pollinator remains unknown. Marsh sandwort is a delicate herbaceous perennial, producing mat-like clusters of erect, slender shoots from underground runners. The vegetative shoots often twine around each other or sprawl over associated vegetation.
Once found in Pierce County, Washington and from San Francisco Bay to the San Bernardino Valley in California, marsh sandwort today is known from fewer than three localities, and its numbers have dwindled to perhaps less than perhaps 50 individuals. As early as 1915, marsh sandwort was considered to be one the rarest plants in Washington, and throughout the first half of 20th Century, botanists stated that it had been “seldom” or “rarely collected” elsewhere. It is classified as endangered in California, Oregon, and Washington. Once found in freshwater wetlands in the coastal areas of all three states, this plant is now found in only one location in California’s San Luis Obispo County, and at last count only three plants were recorded. Increased urbanization can be blamed for these huge losses, as can off-road vehicle use and the threat from invasive plants.
Experimental studies have shown that marsh sandwort propagates readily from vegetative cuttings, using single shoots bearing adventitious roots at the base. Experimental transplantation has been successful at one site with suitable habitat, using 1 gallon containers. Twenty plants were established in 2003 at one site, of which sixteen have survived.