Common (Translated Scientific) Name: Water Knotweed - Broadleaf Arrowhead Riverine Wet Meadow

Colloquial Name: Riverine Forb Wet Meadow

Hierarchy Level:  Association

Type Concept: This association is currently only described from Mississippi National River and Recreation Area, Minnesota. Additional global information will be added as it becomes available. This forb-dominated wetland usually forms dense, low herbaceous stands. However, it occurs mostly in floodplains and is subject to periodic severe flooding which can kill some of the existing plants and open up the herbaceous canopy. In the absence of repeated disturbance, the herbaceous stratum fills in the open areas, first with annuals or short-lived perennials and eventually with perennials. Shrubs are not common but can have up to 25% cover in some stands. Trees are widely scattered or absent. Polygonum amphibium is the most common species in this community and can form nearly solid canopies 0.5-1 m high. Sagittaria latifolia and other low forbs can be abundant under this canopy. Bolboschoenus fluviatilis and Sagittaria latifolia are very common but do not have more than 50% cover. The perennials Carex lacustris, Leersia oryzoides, Phalaris arundinacea, Phragmites australis, Sparganium eurycarpum, Stachys tenuifolia, and Typha spp., and the annuals/biennials Amaranthus tuberculatus, Bidens cernua, Bidens frondosa, Calystegia sepium, Eragrostis hypnoides, Polygonum pensylvanicum, Sicyos angulatus, and Xanthium strumarium can all be found in this community. Woody species include Salix interior and small to large floodplain trees. This association is found along the Mississippi, Minnesota, and Vermillion rivers and some tributaries in areas protected from constant exposure to currents. This can include lakes or depressions in the floodplain as well as backwater areas of the main rivers. Stands are often flooded for a few to several weeks each year but will not persist in the face of repeated exposure to strong currents and deposition and scouring. Soil is rich fine-textured alluvium which can encourage lush vegetative growth.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This association was identified based on information collected during the vegetation mapping project at Mississippi National River and Recreation Area. It lacks characterization based on data from a larger region and thus lacks global information.

Similar NVC Types: No Data Available

note: No Data Available