It is my understanding that Texas, after declaring their independence by seceeding from the United States, reverted back to their 2nd Texas Republic flag as their banner. This was a Blue Flag with a single White Star in the Center.
It was this flag of independence that Harry McCarthy saw in Montgomery, Alabama and dubbed the "Bonnie Blug Flag". This flag is still repersented in the Present day Texas State Flag "Mrs Wigfall's Dress" in the Blue band with the single star.