Physiognomy and Structure: No Data Available

Floristics: The canopy, subcanopy, shrub, and herbaceous layers of stands of this association are often well-developed. Dominant canopy species always include Liquidambar styraciflua and Liriodendron tulipifera, while Acer floridanum (= Acer barbatum) (in the southern part of the range), Platanus occidentalis, and Acer rubrum var. rubrum may also make up significant amounts of the canopy. This community type exists as a continuum between two subtypes, i.e., the tuliptree subtype and the sweetgum subtype. In some examples, only one or the other dominates the canopy. However, in many examples, both are equally dominant. Other common species in the canopy and understory include Ilex opaca var. opaca, Aesculus sylvatica, Carpinus caroliniana ssp. caroliniana, Carya cordiformis, Cornus florida, Fagus grandifolia, Juglans nigra, Betula nigra, Morus rubra var. rubra, Ostrya virginiana (= var. virginiana), Oxydendrum arboreum, Pinus echinata, Prunus serotina var. serotina, Quercus alba, Quercus rubra var. rubra, Ulmus rubra, Ulmus americana, Ulmus alata, Juniperus virginiana var. virginiana, Nyssa sylvatica, Fraxinus americana, Halesia tetraptera var. tetraptera, Arundinaria gigantea (= ssp. gigantea), and Fraxinus pennsylvanica. Euonymus americanus, Lindera benzoin var. benzoin, and Corylus americana are common and dominant in the shrub layer. Other shrub species that may be present include Viburnum acerifolium, Viburnum nudum var. nudum, Viburnum prunifolium, Viburnum rufidulum, Hamamelis virginiana, Asimina triloba, and Ilex decidua, among others. On the most acidic sites of the Maryland Coastal Plain, Clethra alnifolia, Vaccinium corymbosum, and Magnolia virginiana may be present. Vines are prominent and include Vitis rotundifolia, Apios americana, Campsis radicans, Aristolochia macrophylla, Bignonia capreolata, Dioscorea quaternata, Gelsemium sempervirens, Parthenocissus quinquefolia (= var. quinquefolia), Passiflora lutea, Smilax bona-nox, Smilax glauca, Smilax hugeri, Smilax rotundifolia, and Toxicodendron radicans ssp. radicans. The herbaceous layer is species-rich and often has good sedge development. Common species in this layer include Thalictrum thalictroides, Trillium cuneatum, Arisaema triphyllum, Asplenium platyneuron var. platyneuron, Botrychium virginianum, Carex spp., Carex impressinervia, Carex striatula, Cinna arundinacea, Collinsonia canadensis, Deparia acrostichoides, Dichanthelium clandestinum, Elymus virginicus, Eurybia divaricata, Galium circaezans, Geum canadense, Medeola virginiana, Packera aurea, Poa alsodes, Polygonatum pubescens, Polystichum acrostichoides, Rudbeckia laciniata, Scutellaria integrifolia, Symphyotrichum prenanthoides, and Viola striata. Thelypteris noveboracensis is a common patch-dominant in the northern part of the range and the Uwharrie Mountains of North Carolina. Carex kraliana, which is evidently near the northern limit of its (primarily southeastern United States) range and is presently known from only two Maryland sites, has been found in this vegetation type at Thomas Stone NHS. A specimen collected at Thomas Stone NHS was cited as a paratype in the description of the species (Naczi et al. 2002). The exotics Microstegium vimineum, Glechoma hederacea, Rosa multiflora, Ligustrum sinense, and Lonicera japonica are common in this community. Other exotics that colonize quickly in disturbed and fragmented versions of this association include Wisteria sinensis, Clematis terniflora, Hedera helix, and Elaeagnus sp.

Dynamics:  The topographic features characteristic of larger-stream floodplains are poorly differentiated in the small-stream habitats of this type, and vegetation zonation is absent to poorly defined. It is unclear what processes create pure sweetgum versus pure tuliptree forests, but dominance is most likely a factor of seed source and amount of flooding (sweetgum may be able to tolerate higher water levels than tuliptree). ~Liquidambar styraciflua - (Liriodendron tulipifera) Ruderal Wet Forest (CEGL007330)$$ is very similar to this community but is usually less than 40 years old and very even-aged with a heavy infestation of invasive exotics and fewer native species in the shrub and herb layer.