The vascular flora of the Roy E. Larsen Sandylands Sanctuary was surveyed during a 16 month period. A catalogue is included of the 544 species in 105 families that were collected on the 881.4 ha preserve located in the Big Thicket region of Texas. Eight woody stands representing variation in the woody communities found on the preserve were analyzed for composition. Density, frequency, basal area, and importance values for each species in the stands within the woody communities are presented.