In spring, the dry stalks of last year's grasses are mixed with the current year's new green growth.
This is what a native grassland should look like--lots of tall grasses with little brush and very few invader species.
Splitbeard Bluestem, Andropogon ternarius, is also present.
All the bluestems flower in late summer and fall. Their fluffy inflorescences make them easy to recognize.
Before the park was established, this prairie area was used to pasture cattle. It was severely overgrazed, with very few native grasses and an abundance of invader or increaser species such as Bitterweed, Croton capitatus, and this Silver-leaf Nightshade (Solanum elaeagnifolium). Now that the area is protected, these weedy species have declined and the native grasses have staged a comeback.
The Mimosaceae is represented in the park by several species of Schrankia and Mimosa. Look for pink "powderpuffs" beginning in late spring or early summer. They have been given the common name of Sensitive Briar because the leaves fold up when disturbed.
One can also find Milkweeds in open areas. This is Asclepias viridis.
The Blackland Prairie and Post Oak Savannah regions of Texas are believed to be more densely brushy and woody than they were before the advent of European settlement. When wildfires are suppressed, woody plants become more abundant. In addition, fencelines which are neither grazed nor mowed provide shelter for woody species and often become "corridors" of colonization for trees and shrubs. The line of trees shown here follows the path of an old fencerow. It makes a narrow strip of woodland visible from the air.
Unusual features of Spiderwort flowers are the bow-tie shaped anthers and the furry filaments. The flowers can be of different colors, depending on soil pH and other environmental factors. The cells of the filament hairs mutate easily and the plants have been grown near nuclear plants as a biological radiation detector.