1.   Drug studies, and with them the competition for patients, have become as common in Tucson as the towering saguaro cactus.

2.   In the path of the flames were hundreds, perhaps thousands of towering saguaros and a panoply of desert wildlife, including the threatened desert tortoise.

3.   Spotting a lizard on the limb of a towering saguaro, Lopez moved stealthily toward his quarry.

4.   Cactuses, such as the towering saguaro, are the spiny symbol of the southwestern United States.