ILLUSTRATED FLORA OF EAST TEXAS - Brit - Botanical Research ...
ILLUSTRATED FLORA OF EAST TEXAS - Brit - Botanical Research ...
ILLUSTRATED FLORA OF EAST TEXAS - Brit - Botanical Research ...
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CURRENT VEGETATION <strong>OF</strong> PINEYWOODS/INTRODUCTION 103<br />
various topographic depressions (Fig. 60). Characteristic tree species include Magnolia<br />
virginiana (sweetbay magnolia), Nyssa biflora (swamp tupelo), and Acer rubrum (red<br />
maple). Typical shrubs and vines include Myrica heterophylla (evergreen bayberry),<br />
Toxicodendron vernix (poison sumac), Smilax laurifolia (laurel-leaf greenbrier), Viburnum nudum<br />
(possumhaw), and Persea borbonia (redbay). In the southern part of the Pineywoods, but<br />
not in the northern, Ilex coriacea (gallberry holly) is also common. Rhododendron canescens<br />
(mountain azalea) and other wild azalea species provide showy flowers in spring.<br />
Woodwardia areolata (netted chain fern) typically dominates the ground layer. Other important<br />
forest floor species are Osmunda regalis (royal fern), O. cinnamomea (cinnamon fern), and<br />
Eleocharis microcarpa (small-fruit spikesedge). Patches of Sphagnum spp. (peat moss) may<br />
be present. Rare species that one may find in Forested Seeps include Spiranthes spp. (ladies’-tresses),<br />
Bartonia texana (Texas screwstem), Parnassia asarifolia (kidney-leaf grass-of-Parnassus), and<br />
Burmannia biflora (northern bluethread). Brooks et al. (1993) described a northern type of<br />
this community which occurs primarily north of southern Angelina County as well as a<br />
southern type which, among other differences, contains Cyrilla racemiflora (swamp titi).<br />
Well known examples of baygalls can be found in the Big Thicket National Preserve in the<br />
Jack Gore Baygall Unit, and along Village Creek (Watson 1975).<br />
IRREGULARLY FLOODED LEVEES AND BOTTOMLAND RIDGES—On the higher and drier portions of<br />
the broad floodplains of major rivers, such as crowns of natural levees, meander scrolls,<br />
and other slightly elevated areas, a plant community similar to that found on Wet-Mesic<br />
Stream Bottoms develops. Soils, often sandy, are usually coarser in texture than soils on the<br />
rest of the floodplain because floodwaters deposit the coarse portion of their sediment load<br />
on the natural levees first when they overflow the riverbank and lose velocity (Mitsch &<br />
Gosselink 1993). Flood duration is shorter and flood frequency lower than for the adjacent<br />
lower portions of the floodplain (see Van Kley & Hine 1998). The hydrologic regime is<br />
“irregularly inundated” (U.S. Army Corps of Engineers 1987) and corresponds to hydrologic<br />
Zone V of Clark and Benforndo (1981). Typical plants include mesic and moderately<br />
flood-tolerant species such as Pinus taeda (loblolly pine), Quercus nigra (water oak),<br />
Liquidambar styraciflua (sweetgum), Q. alba (white oak), Q. pagoda (cherry-bark oak), and<br />
occasionally, Q. falcata (southern red oak). “Canebrakes,” thickets of Arundinaria gigantea<br />
(giant cane or switch cane), are common.<br />
SEASONALLY FLOODED RIVER FLOODPLAINS—Seasonally Flooded River Floodplains, the most<br />
extensive ecological type on most bottomland landscapes, occupies the broad flat portions<br />
of the floodplains of major rivers (Fig. 61). These communities correspond to the “sweetgum-oak<br />
floodplains” of Ajilvsgi (1979), “Floodplain hardwood forests” of Marks and<br />
Harcombe (1981), and “river bottom communities” of Nixon (2000). The hydrologic<br />
regime largely corresponds to Zone IV (Clark & Benforndo 1981), which is described as<br />
“seasonally inundated” (U.S. Army Corps of Engineers 1987), while lower Quercus lyrata<br />
(overcup oak)-dominated areas correspond to the “regularly flooded” hydrologic Zone III.<br />
Soils, subject to seasonal flooding, are generally loamy to clayey. Natural forests are a rich<br />
mixture of flood-tolerant deciduous hardwoods, including Quercus phellos (willow oak),<br />
Q. laurifolia (laurel oak), Q. lyrata, Q. michauxii (swamp chestnut oak), Liquidambar styraciflua<br />
(sweetgum), Ulmus americana (American elm), Nyssa biflora (swamp tupelo), and Acer<br />
rubrum (red maple). Overcup oak is the most flood-tolerant of the bottomland oaks and<br />
may form pure stands on lower portions of the floodplain and in slight depressions where<br />
flooding is more prevalent. Ilex decidua (deciduous holly), Styrax americana (American<br />
snowbell), and Crataegus opaca (mayhaw) are common understory shrubs. Ground cover