Nongame and Rare Species Program: Rare Plant Communities of Texas
Edwards Plateau: Streamside Fens
Global Rank: G1
Description: Fens, or calcareous spring and seep-influenced herbaceous wetlands, occur infrequently along creeks and rivers of the Edwards Plateau in central Texas. Most examples are known from the upper Guadalupe River watershed in Kerr County. The substrate includes marl clays and gravels over limestone bedrock. Sites occur as mats of vegetation in mucky soils originating at nearby springs. Vegetation can extend into the stream as patchy islands among small braided channels. Calcium carbonate cake layers can be present. These sites are dominated by sedges, grasses, and forbs. Dominant plant species can include Cladium mariscus ssp. jamaicense, Eleocharis rostellata, E. montevidensis, E. geniculata, Rhynchospora capillacea (a disjunct species), R. nivea, R. colorata, Schoenus nigricans, and Muhlenbergia utilis. Other herbaceous plants associated with this community include Andropogon glomeratus, Bidens laevis, Boehmeria cylindrica, Carex edwardsiana, C. muhlenbergii, Centella asiatica, Dichanthelium acuminatum var. lindheimeri, D. oligosanthes var. scribnerianum, Fimbristylis puberula, Fuirena simplex, Helenium microcephalum var. microcephalum, Juncus texanus, Ludwigia repens, Lythrum ovalifolium, Mitreola petiolata, Nasturtium officinale, Panicum virgatum, Paspalum pubiflorum, Pluchea odorata, Symphyotrichum praealtum, Verbena scabra, and Verbesina lindheimeri. A few woody species may grow in these wetlands including Cephalanthus occidentalis, Lindera benzoin, Platanus occidentalis, and Salix nigra.
Species of Interest: Bladderwort (Utricularia gibba), Low Nutrush (Scleria verticillata)