What's Rare in the Water...
by Kathy Ahlenslager
When I look into the clear waters of Pend Oreille County, I try to find bladderworts and water awlworts. Although these rare aquatic plants are submersed, their flowers and fruits rise above the water’s surface. Flat-leaved bladderwort (Utricularia intermedia) and the lesser bladderwort (U minor) occur in a couple of lakes on private land in Pend Oreille County. Water awlwort (Subularia aquatica) was recently found in a lake in the county on the Colville National Forest. Plants may be truly rare in an area or rare because no one has looked for them. These three rare plants are small and could be easily overlooked.
The carnivorous bladderworts capture small animals in bladder-like traps. Once a prey animal triggers hairs attached to a door on a trap, the door opens. Prey and water are sucked into the trap in fifteen thousandths of a second. Leaves of the two rare bladderworts are about an inch long and can be distinguished from the two-inch-long leaves of the common bladderwort (Utricularia vulgaris). Bladders of the lesser bladderwort occur on the leaves, while those of the flat-leaved bladderwort are borne on separate branches. The two rare bladderworts are found in a handful of counties in Washington. Look for their snapdragon-like yellow flowers July and August.
Water awlwort (Subularia aquatica) looks like a tuft of rounded quill-like leaves about two inches long. Although it’s considered an annual, plants may overwinter in lakes and slow-moving streams. A relative of mustard, the 4-petaled white flowers of water awlwort bloom June through August. Plants reach about six inches high. In Washington it’s only known from one site each in four counties.
The Washington Natural Heritage Program maintains a database of rare plant sighting for the state and the on-line “Field Guide to Selected Rare Plants of Washington”(http://www.dnr.wa.gov/nhp/refdesk/fguide/htm/fgmain.htm). In addition, Washington State Department of Ecology developed the on-line, “Aquatic Plant Identification Manual for Washington’s Freshwater Plants” (http://www.ecy.wa.gov/programs/wq/plants/plantid2/index.html). Both of these are great resources to consult, after I’ve looked into the clear waters of Pend Oreille County.