Norman,
You've gotten some great answers from Stephen and Ken. I'd like to add, I recall reading a "Slave Narrative" where a female teenage slave recalled seeing the Texans in their Butternut/Brown uniforms approaching the battle of Honey Springs, July 17, 1863. She stated that you could tell they were Texans because they wore these butternut uniforms. The Indians and Cabell's Arkansas, apparently had a different appearance. The Texas troops at Honey Springs were the 20th TX Cav Dsmtd, the 5th Texas Partisan Rangers, the 29th Texas Cavalry, Gillette's and Scanland's Squadrons of Texas Cavalry and Roswell's Texas/Indian Battery.
Jim Martin