Even though WTU has extensive and comprehensive vascular plant collections for the Pacific Northwest, a few groups within this collection would benefit from efforts to update and expand their representation. The aquatic vascular plants are one such group, and their need for improvement results from a mix of factors that include their typically late flowering/maturation period, the challenges associated with accessing them for collection, and perhaps their reputation of being somewhat challenging to identify accurately.
Starting in 2004, David Giblin, with assistance from Ben Legler, initiated a series of collecting trips aimed to document the diversity and distribution of Washington's aquatic vascular plants. These trips built on previous work by WTU Research Associate Peter Zika, who has done extensive aquatics collecting throughout Washington State. David, Ben and targeted the rivers and small lakes of Skagit counties in 2004, and their efforts produced dozens of new county records for WTU. Tad Dillhoff joined us in the field for one of these outings.
The highlight of the 2005 trips was a two-day outing to southwestern Washington that focused on the freshwater intertidal zone found in Grays Bay on the Columbia River, and the emergent and submergent flora of Silver Lake, located west of Mt. Saint Helens. Cathy Maxwell graciously hosted and joined David, Ben and Peter Zika in the field, as well as arranged for canoes and a put-in point at Gray's Bay. Some of the interesting species that we collected there were water mudwort (Limosella aquatica), water pygmyweed (Crassula aquatica), bristle-like quillwort (Isoetes echinospora), and four species of pondweed (Potamogeton spp.) At Silver Lake, we rented a small boat with outboard motor to visit several areas around the lake. Notable collections there included false loosestrife (Ludwigia palustris), the native common bladderwort (Utricularia vulgaris), the introduced swollen bladderwort (Utricularia inflata) and kneeling angelica (Angelica genuflexa).
In 2006, David and Ben made collections in aquatic habitats on both sides of the Cascades. In the East Cascades of Kittitas County, they were joined by NSF REU intern Jessica Ni and Don Knoke on a trip to the Swauk Pass area, and Barbara Williams participated on a trip to the South Fork Meadows area on the south side of Cle Elum Ridge. West Cascades localities included the north end of Baker Lake in Whatcom County, where notable collections included mountain mares-tail (Hippuris montana), and wool grass (Scirpus cyperinus). David and Ben also visited several small lakes in Skagit County (Lake Campbell, Cranberry Lake, Heart Lake), where among their collections was yellow pitcher plant (Sarracenia flava). Interestingly, this native of the southeastern U.S. has been intentionally introduced into sphagnum bogs of western Washington by carnivorous plant enthusiasts.
Over the course of this project, we have added over 500 aquatic vascular plant specimens to WTU's collections, some of which are now being used by researchers working on the Flora of North America project. We have documented occurrences of rare plants tracked by the Washington Natural Heritage Program, and have expanded our knowledge of the distribution of both native and nonnative aquatic species here in Washington.