Special thanks to Bill Carr for preparing this material. Additional notes by NPAT.
This 31-acre tract lies along U.S. 77 south of Tanglewood in northwestern Lee County, Texas. It is longitudinally bisected by an abandoned railroad bed from which ties and rails have been removed, and is bordered on the east by a small intermittent tributary of Brushy Creek. The property lies on very gently undulating topography at elevations between about 420 and 450 feet. According to the Austin Sheet of the Geologic Atlas of Texas (Proctor et al., 1981), the entire site is underlain by the Sparta Sand, an Eocene formation composed mostly of fine to very fine grained quartz sand. According to information provided by the Natural Resources Conservation Service the principal soil is a sandy Alfisol of the Silstid Series. Two major vegetation types are present on this small tract. The first is a grassland component of a post oak (Quercus stellata) savanna. This community covers the western half or two-thirds of the property. The eastern edge, along the nameless drainage, supports a deciduous riparian woodland that includes some patches of herbaceous wetland vegetation.
The grassland is dominated by the two expected midgrasses, little bluestem (Schizachyrium scoparium) and brownseed paspalum (Paspalum plicatulum). Common forbs at midsummer include maroon gaillardia (Gaillardia amblyodon), pinweed (Lechea mucronata), lazy-daisy (Aphanostephus skirrhobasis), hog croton (Croton capitatus), spotted beebalm (Monarda punctata), mock-bishop (Ptilimnium nuttallii), weak sunflower (Helianthus debilis), soft goldenaster (Heterotheca pilosa), camphor goldenaster (Heterotheca subaxillaris) and scratch-daisy (Croptilon divaricatum). Dozens of other grasses and forb species are present.
Perhaps the most unusual species observed during this survey is hoary milkpea (Galactia canescens), a species endemic to open areas on sandy substrates in South Texas. This occurrence, of a few dozen plants in sparingly vegetated sand may represent the northern limit of the species’ range. Few exotics are present, and those that are present probably don’t represent a serious threat to community integrity. At present, seedlings of woody plants, most notably eastern persimmon (Diospyros virginiana) and Texas black hickory (Carya texana) are locally common. Bordering this grassland in one area is a patch of the woodland component of the post oak savanna system, which in addition to the nominative species also contains numerous Texas black hickory and a few blackjack oak (Quercus marilandica), as well as a dense shrub layer of yaupon (Ilex vomitoria), American beautyberry (Callicarpa americana) and various woody vines.
Components of the canopy include water oak (Quercus nigra), American elm (Ulmus americana) and sugar hackberry (Celtis laevigata var. laevigata), but which is dominant and what other tree species are present were not determined. The fairly dense shrub layer includes wax-myrtle (Myrica cerifera), yaupon, flowering dogwood (Cornus florida) and other common species. Wetland spots within the woodland are formed by alteration of drainage patterns by the railroad embankment. Some such spots are dominated by velvet-leaf panicum (Panicum scoparium); others contain common rushes (Juncus spp.) and smartweeds (Polygonum spp.).
No globally-rare plant species have been reported from this site to date. Six species ranked G3/T3 or rarer are currently known from Lee County, one of which is known from deep sand sites such as the Tanglewood savanna.
The Tanglewood site is a very good example of post oak savanna grassland. It is dominated by native perennial midgrasses, has high species diversity but only a few exotics, and might readily be managed with fire during periods of westerly winds. The only reservation about a quality assessment is that there is nothing to compare the site to, since the botanical and conservation communities have paid scant attention to post oak savanna communities in Texas and thus qualitative assessments of other sites are lacking.
See the Flora of Tanglewood Prairie.
A gallery of the flora of Tanglewood Prairie — click on a photo to see it larger.