It was a potent testimonial to the proselytizing powers of Marina Keet -- artistic director of the Spanish Dance Society USA -- to see more than 150 disappointed would-be spectators lined up outside the Smithsonian's jammed Baird Auditorium Saturday night for the society's newest program. The hall's 500-plus seats had also been filled for a matinee the same day.

The turnout, of course, bore witness to the growing popularity of Spanish dance hereabouts, an increase by no means accidentally related to Keet's impassioned advocacy over the last decade. The society is an American branch -- founded by Keet and Joanne Petrie in 1982 -- of an international organization dedicated to the propagation of and training in Spanish dance. The Washington chapter is unique in embracing not only education but a performing company -- one that has become an admired staple of the local dance scene and distinguished itself also in visits to such venues as the Boston Museum of Fine Arts, the Juilliard School and New York's Museum of Natural History.

The pedagogic aspect of the society's activity typically rubs off on its performances. If the downside of this is an uneven mix of theatrical professionalism and schoolroom blandness, the upside is that one does actually learn more about what one sees on stage in these concerts than in most others. The extensive program notes, and Keet's explanations and demonstrations, make for an enhanced appreciation of an artistic tradition that is far richer and more complex than most concertgoers are apt to realize. Indeed, this seems to be part of the allure of the society's presentations -- people feel they're getting understanding along with enjoyment, and it's something they crave.

A leitmotif of Keet's crusade on behalf of Spanish dance has been to show the public that flamenco -- as magnetic and important as it is -- is only part of a vast tapestry of historical, provincial, folk, classical and contemporary Spanish forms. This latest program concentrated on two main tributaries -- the escuela bolera, the Spanish "dialect" of classical ballet, originating in the 18th century; and flamenco. Each was illustrated with an extended suite of dances, both solos and ensemble numbers, knit into a more or less continuous flow. Preceding each half was an accessible aperitif in the form of excerpts from zarzuelas, which are like danced operettas.

There was also a special treat in the presentation by guest artist Michael Lorimer, a Segovia protege whose expertise lies with the baroque guitar, an instrument of singularly dulcet timbre and charm. Lorimer first explained his discovery of a trove of Spanish dance music of the 18th century in a long-lost manuscript that turned up in Mexico, and then played extracts -- gracefully ornamented and gently polyphonic pieces of instant appeal. He was joined in one sequence by guest dancer Alan Tsaarda Jones, attired in full rococo regalia, for a beguiling sampling of the dances themselves, fusing sprightliness and patrician decorum.

Highlights of the escuela bolera portion included Nancy Sedgwick's demurely coquettish "La Macarena" solo; Ziva Cohen's elegant, spirited "Ole de la Curra"; the especially lively and piquant fluency of Lourdes Elias in the "Zapateado de Maria Cristina"; and the floral effusion of the concluding ensemble, "Panaderos de la Flamenca."

In the flamenco sequence, the virtuosic Jaime Coronodo drew voluble shouts from the crowd with his impetuous opening "Solea," dramatically contrasting measured restraint with accelerating febrile intensity. The climax, also cheered, was the "Peteneras por Cana," an ardent duet for Cohen and Coronado preceding the final "Soleares," danced by the entire troupe. Singer Jorge Porta and a cadre of five instrumentalists contributed firm musical support.