This plant grows in all ten vegetational areas of Texas!
The name comes from the way that its seedpods grow and curve.
Other common names are green-flowered milkweed, and spider antelope horns (in case one animal in the common name is not enough, I guess). If I got to name it, I would have called it Texas snowball.
Its Latin name is Asclepias asperula. It is listed in Toxic Plants of Texas, because it can be toxic to livestock. Fortunately, it tastes bad to them, and they will only eat it if they are penned up in an area with lots of milkweed and not much else.
While it may not be good for livestock or humans, being a milkweed, it is very important to monarch butterflies! It is also attractive to native bees, which, we are learning, are very important to the environment as a whole.