This is another weed in the pasture where the horses suffered liver damage that I can't name. I had been lumping it in with Teaweed (Sida rhombifolia) to which it is similar, but I believe it is a different plant. It also somewhat resembles Lantana which is known to cause liver damage, however its leaves have no odor when crushed and it forms seed pods not berries. The photos are not good, so I will try again if need be.
Certainly looks a lot like it and it does grow in Fort Bend County. If that is the correct ID then it is in the same family as Sida rhombifolia, which would account for the similarity in appearance.