Reconstruction of fifteen star Secession Flag in use in Texas during February and March of 1861.  This version does not include elements from the Flag of the Republic of Texas.
Frank Wilson Kiel, "A Fifteen-Star Texas Flag: A Banner Used at the Time of Secession: February 1861 and March 1861," The Southwestern Historical Quarterly 103, no. 3 (January 2000): 356-365.
Glasshouse