SALT MARSHES Vegetation/Algae: Nonwoody, salt-tolerant plants; principal species are smooth cordgrass (on Atlantic side) and black needlerush; above mean high water level are numerous vascular plant species in addition to black needlerush; several hundred species of benthic microalgae and phytoplankton; a few species of large, multicellular seaweeds; occasional mangroves in warmer areas.