Texas Bindweed, also known as Convolvulus equitans, is common in praries and a member of the morning glory family. This plant is an annual and blooms in April through October. It is a vine that twists around weeds and shrubs and is capable of blocking so much light that these plants die. I thought it was one of the most beautiful wildflowers we saw on our walk through campus.
http://www.inaturalist.org/observations/5434101