Plants of Purshia tridentata and Purshia stansburyana, 2 shrub species from the western United States, naturally display eccentric stem growth. The purpose of this study was to quantitatively document stem eccentricity for these 2 species. Stem segments were obtained from 3 different plants of each species at locations in central Utah. Each stem was sawed into 8-mm sections and photographed for analysis. Every stem section was then marked at a 36° interval to produce 10 wedge-shaped sectors. The areas of each sector were determined and analyzed. Stem segment areas were about 40, 60, and 100 mm² for stem diameters of 6, 8, and 11 mm, respectively, for both species. Consecutive 8-mm segments were compared at 6 and 11 mm for both species. Absolute differences between paired segments ranged between 0.0 and 12.0. On average, 43% of all pairs had absolute differences above 0.40. These results suggest marked differences between consecutive segments. The eccentric growth percentages were also the same for both species. Mean eccentric percentages for 6-mm-diameter segments were 43.4% and 49.6% for the 2 species. Moreover, 11-mm-diameter segments of P. tridentata and P. stansburyana had mean eccentric percentages of 36.4% and 34.0%, respectively. Overall, 81% of all stem segments showed eccentricity. Many long-lived desert shrubs of the western United States exhibit a wide range of wood anomalies. These wood anomalies may be endemic in these species.