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

146 INTRODUCTION/FUTURE OF BLACKLAND PRAIRIE
(meadow flax), Marshallia caespitosa (Barbara’s-buttons), Oenothera macrocarpa (Missouri
primrose), Paronychia jamesii (James’ nailwort), and Thelesperma filifolium (greenthread). At
some seasons, these outcrops have the aspect of barren eroded rock; in the spring, however,
they are covered with spectacular displays of color.
THE BLACKLAND PRAIRIE AS A MOSAIC
As described above, there is considerable variation in the tall grass prairie communities of
the Blacklands (Diamond & Smeins 1993), and there is disagreement about specific community
types (Simpson & Pease 1995). However, common dominant grasses of most of this
tall grass prairie ecosystem include Schizachyrium scoparium (little bluestem), Andropogon
gerardii (big bluestem), Sorghastrum nutans (Indian grass), Panicum virgatum (switch grass),
Tripsacum dactyloides (eastern gamma grass), Sporobolus compositus (tall dropseed), Eriochloa
sericea (Texas cup grass), Paspalum floridanum (Florida paspalum), and Tridens strictus
(long-spike tridens) (Collins et al. 1975). Despite similarities in general aspect and even the
occurrence of certain species over broad areas, the particular community present and the
dominants observed can vary considerably even over short distances, primarily on the basis
of differences in soil. Localized patches of a community type well beyond its main zone of
occurrence are common, based on soil or other factors. Therefore, most of the Blackland
Prairie is a complex mosaic of tall grass communities; an example of this can be seen in
northern Grayson County where four of the community types discussed above can be seen
within a few miles.
WOODED AREAS OF THE BLACKLAND PRAIRIE
Although prairie vegetation predominates, some wooded areas are also natural components
of the undisturbed Blackland Prairie. Examples include bottomland forests and wooded
ravines along the larger rivers and streams, mottes or clumps in protected areas or on certain
soils, scarp woodlands on slopes at the contact zones with the Edwards Plateau and Lampasas
Cut Plain, and scattered upland oak woodlands similar to the Cross Timbers (Gehlbach 1988;
Nixon et al. 1990; Diamond & Smeins 1993). In areas such as Dallas, where the Austin
Chalk forms a conspicuous escarpment or bluff, a characteristic woody vegetation is also
found in the varied microhabitats associated with this topographic feature. Kennemer (1987)
noted that Fraxinus texensis (Texas white ash), Quercus sinuata var. breviloba (shin oak), and
Ulmus crassifolia (cedar elm) are dominant. Other noteworthy woody plants of the escarpment
include Cercis canadensis var. texensis (Texas redbud), Juniperus ashei (Ashe’s juniper),
Morus microphylla (Texas mulberry), and Ungnadia speciosa (Texas buckeye). Farther south, in
Bell, Hill, and McLennan counties, the Austin Chalk scarp vegetation is similar. Depending
on slope and moisture conditions, characteristic species may include Celtis laevigata (sugarberry),
Diospyros texana (Texas persimmon), Forestiera pubescens (elbow-bush), Fraxinus
texensis (Texas white ash), Ilex decidua (deciduous holly), Juniperus ashei, J. virginiana (eastern
red-cedar), Ptelea trifoliata (hoptree), Quercus buckleyi (Texas red oak), Q. fusiformis (Plateau
live oak), Q. sinuata var. breviloba, and Ulmus crassifolia (Gehlbach 1988).
THE FUTURE OF THE BLACKLAND PRAIRIE
As indicated earlier, with the exception of preserves, small remnants, or native hay meadows,
almost nothing remains of the original Blackland Prairie communities. Unfortunately, the few
small existing remnants are still being lost due to a variety of causes. An example is the
destruction of Stults Meadow in Dallas, studied in detail by Laws (1962) and Correll (1972a).
According to Diamond et al. (1987), all of the tall grass community types of the Blackland
Prairie are “… endangered or threatened, primarily due to conversion of these types to row