Pacific mosquito fern (Azolla filculoides), an exotic aquatic fern, has been found in Ulster County this summer by DEC Riparian Buffer Coordinator Kevin Grieser. He has it occurring in two water bodies near New Paltz. These are the first reports for this species in Ulster County according to the NY Flora Atlas. This species, well established in Central and Western New York, may be extending its range in the lower Hudson area. Its distinctive red leaves can be seen covering the surface of the water. The similar Azolla caroliniana, a native species, has only been found in Oswego County and can be distinguished by having multicellular hairs on the leaves instead of hairs of one cell on A. filiculoides. A microscope is usually needed to see the difference. Photos by Kevin from the plants on the Swartkill, east of New Paltz, are below.