I expect Falconer cataloged what he found, and perhaps the plant community associations. There was a typo in my scan (had to print the GIF then scan it to Word and correct it). Should have said their "baggage" was siezed in New Mexico--perhaps it was never returned? Had to list stuff from memory? Lots of oaks in Texas that's for sure! For art of the period that includes wonderful botanical detail, have you seen the border survey by William H. Emory? Map of Texas and the countries adjacent* has wonderful etchings--more cactus than oak, but about the same period. 1844.

*full title in catalog: Map of Texas and the countries adjacent / compiled in the Bureau of the Corps of Topographical Engineers, from the best authorities, for the State Department, under the direction of J.J. Abert by W.H. Emory ; W.J. Stone, sc.

SRS