Houstonia micrantha looks a good match ..
http://www.usm.edu/herbarium/j...
Others in TX..
http://plants.usda.gov/java/pr...
Houstonia acerosa .. no match
http://www.thehibbitts.net/ter...
Houstonia correllii .. can't find but there's a description of some Houstonia on google books..
http://books.google.co.uk/book...
Houstonia croftiae .. google doesn't recognise it. I found it on an edu site, no flowers but leaves.
http://www.biosci.utexas.edu/p...
Houstonia humifusa .. no match
http://www.wildflower.org/gall...
Houstonia parviflora .. don't think so
http://repository.tamu.edu/han...
http://www.wildflower.org/gall...
Houstonia purpurea .. no match
http://plants.usda.gov/java/pr...
Houstonia pusilla .. no match
http://plants.usda.gov/java/pr...
Houstonia rosea .. no match
http://www.pbase.com/cmf46/oly...
Houstonia rubra .. no match
http://plants.usda.gov/java/pr...
Houstonia subviscosa .. no match
http://www.biosci.utexas.edu/p...
Houstonia wrightii .. no match
http://plants.usda.gov/java/pr...
http://swbiodiversity.org/sein...
