Sand barrens are herbaceous upland communities that develop on unstable or semi-stabilized alluvial sands along major rivers like the Mississippi and Wisconsin. They are partly or perhaps wholly anthropogenic in origin, occurring on sites historically disturbed by plowing or very heavy grazing. Unvegetated "blow-outs" are characteristic features. Barrens, dry prairie, and sand prairie species such as false-heather (Hudsonia tomentosa), bearberry (Arctostaphylos uva-ursi), sedges (Cyperus filiculmis and C. schweinitzii), sand cress (Arabidopsis lyrata), three-awn grasses (Aristida spp.), rock spike-moss (Selaginella rupestris), and the earthstar fungi (Geaster spp.) occur in this community type. Many exotics are often present and rare disturbance-dependent species such as fameflower (Phemeranthus rugospermus) are found in some stands.
