ILLUSTRATED FLORA OF EAST TEXAS - Brit - Botanical Research ...

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SOIL-RELATED GEOLOGY, PINEYWOODS, POST OAK SAVANNAH/INTRODUCTION 51 grass, the soils are black or dark gray, reflecting high levels of organic matter. The predominantly clayey soils are Vertisols which crack to the surface when dry. The soil surface has the microtopographic features known as “gilgai,” which trap water during periods of intense rainfall. Limited areas have a thin loamy surface layer or mounds of wind-deposited sediments or even a surface of sandy material. In general, the Beaumont underlies “a flat, featureless, treeless coastal plain extending in a belt about 40 miles wide about 10 to 15 miles from the coast....” (Sellards et al. 1932). However, on the poorly drained Beaumont flats between rivers on the southern edge of East Texas (parts of Hardin, Harris, Jasper, Liberty, Newton, and Orange counties), extensive flatwoods wetlands with pines, hardwoods, and often abundant palmetto occur (Moulton & Jacob no date; Watson 1975). Some of these areas are classified as Wetland Longleaf Pine Savannahs by Bridges and Orzell (1989b) or Wet Pine Savannahs by Van Kley (see page 97). Also, in extreme southeastern Texas (on the southern margin of East Texas) and on extensive areas near the coast just south of East Texas, both the Beaumont and the next layer, the Lissie, in places support Coastal Prairie with prairie “potholes.” These are unique microtopographic depressions that form important areas of wetlands. These unusual features, which often occur in combination with mima mounds (see page 65) and intermound flats, are rapidly being destroyed by land leveling for agriculture and by urbanization (e.g., the area around Houston). “This complex pattern, formed thousands of years ago by ancient rivers and bayous, and modified through time by climatic (especially wind) and biotic forces, is an irreplaceable geological legacy. Once these complexes are gone, there is no replacing them” (Moulton & Jacob no date). Because of moisture differences associated with microtopographical change, plant diversity in the area of these complexes can be quite high. In areas of Wetland Longleaf Pine Savannahs, longleaf pines are sometimes confined mostly to mima mounds or other relatively drier areas. A number of additional physiographic features, including meander belts and barrier bars, are well-preserved and easily recognized in the Beaumont Formation (Garner 1967). LISSIE FORMATION—(including Montgomery and Bently)—Like the Beaumont, the Lissie, a slightly older layer located further inland, is a Pleistocene age formation. It is composed of thick beds of sand with lenses of gravel and some clays, sandy clays, and silt (Sellards et al. 1932; Solis 1981; Smeins et al. 1982). The Lissie represents continental and delta deposits laid down by floodwaters during glacial times. It outcrops “in a belt about 30 miles wide parallel to the present coastal plain about 50 miles from the coast” (Sellards et al. 1932). Topographically, the Lissie generally forms a nearly featureless plain (Sellards et al. 1932). However, mima mounds (see page 65) can be present, adding to habitat diversity (Bridges & Orzell 1989b). Soils of the Lissie Formation are mainly Alfisols with a scattering of Ultisols. These soils have a loamy to sandy surface layer over a loamy subsoil. Extensive areas are dissected by wet to ponded lows that are covered with water during most of the cool season. Alfisols occupy the depressions, drainage ways, and some of the lower mounds, while Ultisols occur on some of the slightly higher ridges. Depending on hydrologic and soil conditions, the Lissie supports quite different vegetation types. In frequently inundated flood plains with calcareous clay soils there are extensive flatwoods wetlands sometimes referred to as “the Flatwoods” (Moulton & Jacob no date; Watson 1975). Some of these flatwoods wetlands are classified as longleaf pine savannah/wet pine savannah/pine savannah wetlands and have floristic ties with bog habitats (Watson 1975; Bridges & Orzell 1989b). Closer to the coast, the Lissie underlies extensive areas of Coastal Prairie. As pointed out by Watson (1975), small-scale but vegetationally quite important topographic/soil differences can be seen in the Lissie—only slightly higher but well-drained sandy ridges (e.g. old levees) support the xerophytic vegetation known as arid or xeric sandylands, while quite nearby hydrophytic vegetation is found in swales underlain by more calcareous, clayrich, poorly drained soils—such variation is well known from the Village Creek area of Hardin County (Watson 1975; also see page 165).
52 INTRODUCTION/SOIL-RELATED GEOLOGY, PINEYWOODS, POST OAK SAVANNAH WILLIS FORMATION—The Pliocene age Willis Formation is composed of continental quartzose reddish sand and gravels (petrified wood can be present) which form well-drained soils. Soils of the Willis Formation are mainly Ultisols with a droughty, coarse sandy surface layer more than 51 cm (20 inches) thick. The Willis sands are somewhat coarser than those of the overlying Lissie. One portion has the particles cemented by iron oxide, which makes it somewhat erosion-resistant and hence ridge-forming (Garner 1967; Solis 1981; Liggio 2002). The result can be sandy ridges and large areas of gravelly soils. Such ridges of residual Willis sands often support upland longleaf pine savannah (Bridges & Orzell 1989b). An example can be seen in the Upland Island Wilderness Area of southern Angelina County, where longleaf pines dominate the canopy. This area is hilly and relatively open with various grasses dominating the ground cover. In the Big Thicket, the Willis also underlies extensive areas of beech-magnolia-loblolly forest. In places where the Willis is underlain by an impermeable layer, seepage areas supporting a bog community can be found—e.g., the Willis-Catahoula contact (Bridges & Orzell 1989a). In the Big Thicket, the dividing line between the “Upper Thicket” and the “Lower Thicket,” sometimes referred to as the Hockley Scarp, is the contact between the Willis and the Lissie formations (Watson 1975). While quite important in the southern part of the Pineywoods, the Willis in Texas has a rather limited surface outcrop—in general, it occurs only east of the Colorado River (Sellards et al. 1932). In the southwestern area of its outcrop (e.g., Colorado and Austin counties), the Willis supports areas of Post Oak Savannah. GOLIAD FORMATION—The Goliad Formation, laid down during Miocene times, is composed largely of sandstone cemented with calcium carbonate. This formation barely enters East Texas, occurring only in the southwest part of the area in DeWitt, Lavaca, and Colorado counties (Sellards et al. 1932). Because of the relatively hard sandstone, the Goliad forms ledges, ridges, valleys, and cuestas (in contrast to the nearly featureless topography which develops from such formations as the Lissie). The ledges have been used as building stone— a possible explanation of why early missions were built at Goliad (Maxwell 1970). In general, in its limited occurrence in East Texas, the sandy soils derived from the Goliad support Post Oak Savannah vegetation. FLEMING FORMATION—(previously sometimes referred to as the Lagarto)—Of upper Miocene age, the Fleming Formation represents stream deposits on a low coastal plain merging seaward with delta deposits (Sellards et al. 1932). It “is composed of gray to light brown calcareous clay and silt, calcium carbonate concretions, and fine to medium-grained calcite-cemented sandstone” (Liggio 2002). It is similar to the adjacent Oakville but has a greater proportion of clay (Sellards et al. 1932). The Fleming outcrops from Newton County west across East Texas to Grimes County and then south. Its average width at the surface is approximately 15 miles (24 km) (Sellards et al. 1932). <strong>Botanical</strong>ly, the Fleming is of significance because the soils developed from it are calcareous (and thus basic) unlike most (but not all) soils in the Pineywoods and Post Oak Savannah. Many of these soils are Vertisols or vertic Alfisols. As a result, a number of calciphilic plants occur on the Fleming. An example is the occurrence of the shadow witch orchid, Ponthieva racemosa, at a unique outcropping of the Fleming on a salt dome (Davis Hill) in Liberty County (Liggio 2002). At other Fleming outcrops (e.g., Jasper, Newton, Tyler counties) unusual occurrences of calciphilic plants are also known (Bridges & Orzell 1989a; J. Liggio, pers. comm.)—e.g., Acer leucoderme (chalk maple) on calcareous clays in Tyler County. Bridges and Orzell (1989a) noted that it “is significant that our Acer leucoderme sites had little or no Magnolia grandiflora or Pinus taeda, two of the major canopy species of southeast Texas mesic ravine forests and a richer flora of infrequent mesic vernal herbs than most such forests.” Some of the interesting herbs mentioned by Bridges and Orzell (1989a) include Erythronium rostratum (yellow trout-lily), Phegopteris hexagonoptera (broad beech fern), Platanthera integra (yellow fringeless orchid), Sanguinaria canadensis (blood-root), Thaspium trifoliatum (purple meadow-parsnip), and Uvularia perfoliata (perfoliate bellwort).
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ILLUSTRATED FLORA OF EAST TEXAS
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ALLDREDGE, LINDA & JACK BATTERBAE,
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We would like to recognize and expr
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ISSN 0833-1475 ISBN 1-889878-12-X S
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“DEEP EAST TEXAS IS AN OLD, QUIET
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Elray S. Nixon E lray Nixon was bor
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ILLUSTRATED FLORA OF EAST TEXAS TAB
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TABLE OFCONTENTS/ PAGE APPENDICES A
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Page 19 and 20: ILLUSTRATED FLORA OF EAST TEXAS OVE
Page 21 and 22: 4 INTRODUCTION/GEOGRAPHIC AREA OF E
Page 27 and 28: 10 INTRODUCTION/MAJOR RIVERS OF EAS
Page 29 and 30: 12 INTRODUCTION/PLANTS TREATED The
Page 31 and 32: 14 INTRODUCTION/GUIDE TO ARRANGEMEN
Page 33 and 34: 16 INTRODUCTION/GUIDE TO SOURCES OF
Page 35 and 36: 18 INTRODUCTION/GUIDE TO GEOGRAPHIC
Page 37 and 38: 20 INTRODUCTION/GUIDE TO ENDANGERED
Page 39 and 40: 22 INTRODUCTION/GUIDE TO GLOSSARY,
Page 41 and 42: 24 INTRODUCTION/GUIDE TO ABBREVIATI
Page 43 and 44: 26 INTRODUCTION/SUMMARY DATA ON FLO
Page 45 and 46: 28 INTRODUCTION/ACKNOWLEDGMENTS Kar
Page 47 and 48: 30 INTRODUCTION/AUTHORS’ NOTE Pre
Page 49 and 50: 32 INTRODUCTION/GENERAL GEOLOGY OF
Page 63 and 64: 46 INTRODUCTION/SOILS SOIL ORDER DE
Page 65 and 66: 48 INTRODUCTION/SOILS, EAST TEXAS B
Page 67: 50 INTRODUCTION/SOIL-RELATED GEOLOG
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Page 77 and 78: 60 INTRODUCTION/SOILS OF BLACKLAND
Page 83 and 84: 66 INTRODUCTION/CLIMATE OF EAST TEX
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Page 95 and 96: 78 INTRODUCTION/GEOLOGY OF PINEYWOO
Page 97 and 98: 80 INTRODUCTION/PRESETTLEMENT, EARL
Page 105 and 106: 88 INTRODUCTION/PRESETTLEMENT VEGET
Page 107 and 108: 90 INTRODUCTION/CURRENT VEGETATION
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102 INTRODUCTION/CURRENT VEGETATION
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104 INTRODUCTION/CURRENT VEGETATION
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106 INTRODUCTION/POST OAK SAVANNAH
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110 INTRODUCTION/GEOLOGY AND SOILS
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112 INTRODUCTION/SOILS, FIRE, AND T
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114 INTRODUCTION/SOILS, FIRE, AND T
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116 INTRODUCTION/ PRESETTLEMENT, EA
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118 INTRODUCTION/VEGETATION OF POST
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124 INTRODUCTION/CONDITIONS TODAY O
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128 INTRODUCTION/RED RIVER AREA are
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130 INTRODUCTION/BLACKLAND PRAIRIE
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132 INTRODUCTION/GEOLOGY OF BLACKLA
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134 INTRODUCTION/PRESETTLEMENT AND
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144 INTRODUCTION/VEGETATION OF BLAC
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146 INTRODUCTION/FUTURE OF BLACKLAN
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148 INTRODUCTION/FUTURE OF BLACKLAN
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150 INTRODUCTION/CADDO LAKE LOCATIO
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152 INTRODUCTION/CADDO LAKE FIG.84/
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154 INTRODUCTION/PRESENT AND FUTURE
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156 INTRODUCTION/BIG THICKET THE BI
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158 INTRODUCTION/BIG THICKET GEOGRA
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160 INTRODUCTION/NATURAL HISTORY OF
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172 INTRODUCTION/SUMMARY DEFINITION
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184 INTRODUCTION/HISTORY OF BIG THI
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190 INTRODUCTION/CONSERVATION IN BI
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200 INTRODUCTION/ORIGIN AND DIVERSI
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228 INTRODUCTION/CONSERVATION IN EA
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234 INTRODUCTION/HISTORY OF BOTANY
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244 INTRODUCTION/BOTANY IN NORTH CE
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246 INTRODUCTION/BOTANY IN NORTH CE
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248 INTRODUCTION/BOTANY AT UNIVERSI
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250 INTRODUCTION/BOTANY AT TEXAS A&
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252 INTRODUCTION/BOTANY AT TEXAS A&
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254 INTRODUCTION/OTHER CONTRIBUTION
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256 INTRODUCTION/CURRENT BOTANICAL
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258 INTRODUCTION/BOTANICAL ART IN E
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