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Acacia berlandieri and Acacia rigidula are two woody legumes, widely distributed over large areas of shrubland in southern Texas, southwestern Texas and northern Mexico. The canopy of A. rigidula acts as a focus for recruitment of other woody and succulent species. The number of woody and succulent species found beneath A. rigidula canopies was greater than the number found in the open areas not associated with these shrubs (24 vs. 20, respectively). There was no difference for A. berlandieri compared to open areas (17 vs. 20, respectively). Eleven woody and succulent species were only found beneath shrub canopies, nine species were found under the canopies of both species and in open al eas and five species were only in open areas. The number of species below the Acacia canopies was related to the size of the canopy. Multiple linear regression indicated that shrub canopy diameter and soil depth under the canopy (for A. berlandieri) and canopy diameter and soil depth in open areas (for A. rigidula) explained 71 to 74% of the variation in the number of woody and succulent species found below the canopy of these shrubs; for each model, canopy diameter was the more important factor. Total soil nitrogen under the two Acacia species was 5 to 13 times greater than that found in the open areas. Of the eight remaining soil characteristics measured, only pH for A. berlandieri and calcium and sulfur for A. rigidula were significantly different under the canopy compared to the open areas.