Late in the evening, I settled into the campground at the Chaparral WMA, just across the Dimmit Co. line in western La Salle County. The camping area had a great variety of plants, some of which were new to me including this neat verbena. Clover's Vervain is like Texas Vervain on steroids--the general shape and structure are the same but the flowers are nearly 3/4" across, probably 3X the size of Texas Vervain. Very attractive. It is primarily a flower of the interior South Texas brush with a few scattered records further north:
http://plants.usda.gov/core/profile?symbol=VECL