Clara Spring, 90, a yoga teacher who taught the discipline to thousands of devotees since coming to California in 1950. She was the author of "Yoga for Today," first published in 1959 and since reprinted several times in many languages. A ballerina as a girl, she became attracted to yoga when she was 17 in New York City. She operated two studios in Southern California, one in Pasadena and one in West Hollywood, and her clientele included several film stars. She also taught for several years at the Claremont Colleges. On Tuesday in West Hollywood.