-Xylem water potentials (+'x), stomatal conductance (gJ), transpiration rates (J), and osmotic potentials at full turgor (i100) and incipient plasmolysis (ito) of Sarcobatus vermiculatus (Hook.) Torr. and Artemisia trzdentata Nutt. ssp. wyomingensis were examined during the growing season in southeastern Oregon. Predawn 4{x (B4'x) declined 3.0 MPa through the summer for Artemisia and 2.0 MPa for Sarcobatus. The lowest Bi/x (-4.0 to -4.5 MPa for Artemisia and -3.5 to -3.8 MPa for Sarcobatus) were similar within species among years. Early in the summer g, and J were similar for both shrubs, but in late summer they were twoto three-fold higher for Sarcobatus. Maximum g, for Artemisia declined exponentially as B4/x decreased, and it was lower than 0.20 cm sec-1 at Bip lower than -3.0 MPa. There was no significant relationship (P < 0.05) between B4'x and g, for Sarcobatus. Artemisia showed limited changes in 4'? (-2.0 to -3.2 MPa) and i,100 (-1.1 to -1.8 MPa) through the summer; for Sarcobatus 4100 and C'. ranged from -1.9 to -3.8 MPa and -2.7 to -6.5 MPa, respectively. This reduction in osmotic potentials in Sarcobatus enables it to maintain turgor and high g, that is critical for completing its growth during a short period when environmental stresses are high. Conversely, Artemisia is evergreen, exploiting moisture that is available during spring and early summer when environmental stresses are typically low and minimizing water loss in summer through reduced g, and leaf area adjustments.