hickory (Carya aquatica), and red maple (Acer rubrum), often with a dense mid-story of ironwood (Carpinus caroliniana). Among the many wildflowers are three irises, yellow iris (Iris pseudacorus), southern iris (Iris virginica), and short-stem iris (Iris brevicaulis), as well as the fragrant ladies tresses orchid (Spiranthes odorata), blue jasmine (Clematis crispa), and the aquatic spatterdock (Nuphar luteum). Although the floodplains in the region share much in common with one another, each river varies with some unique elements and plant species. The Trinity River basin in particular stands out in contrast to others with calcareous, relatively high pH, alkaline soils supporting vegetation that is seldom seen in other watersheds, including bois d'arc also called horse apple (Maclura pomifera), blueberry hawthorn (Crataegus brachyacantha), cedar elm (Ulmus crassifolia), and Texas sugarberry (Celtis laevigata). Baygalls (aka: bay-gallberry holly bogs in part; Acid bog baygalls): With dense undergrowth and twisted vines growing in stagnant, blackwater, acid bogs, under a shadowy canopy of swamp tupelo and cypress, baygalls are often said to exemplify and epitomize the Big Thicket. Baygalls typically form at the base of slopes where seeps, springs, and rainwater drain onto the margins of the flat floodplains and bottomlands, away from the main channels. The drainage from the slopes maintain saturated, muddy soils in these already damp and humid areas, where pools, bogs, and stagnant drainages form in depressions on the flat landscape. With sphagnum mosses and high peat content, baygall soils and water have very high acidity, pH levels of 4.5 are common. The high acid levels are a significant factor in distinguishing baygalls from the floodplain and flats ecosystems. Although baygall waters are generally shallow and torpid, they sometimes form small, highly acidic blackwater streams, slowly moving into the larger creeks and bayous. Hanging bogs occur where water pools on irregular flat and low areas on the slopes above the bottomlands. The name baygall is derived from sweetbay magnolia (Magnolia virginiana) and sweet gallberry holly (Ilex coriacea). These and swamp titi (Cyrilla racemiflora) are dominant and other common shrubs include southern bayberry (Myrica cerifera), water willow (Decodon verticillatus), red bay (Persea borbonia), and Virginia sweetspire (Itea virginica). Vines like muscadine grape (Vitis rotundifolia), supplejack or rattan-vine (Berchemia scandens) can grow impressively large. Larger trees include swamp tupelo (Nyssa biflora) and bald cypress (Taxodium distichum). In addition to the prominent fragrant water-lily (Nymphaea odorata), baygalls harbor many small and obscure wildflowers such as