"Flamenco Puro," the dance show that opened a week's run at the Warner Theatre last night, embroils the stage in its volcanic heat, fury and force. The action may simmer slowly and quietly for a time, but one can feel the bubbling torrents underneath gathering for eruption. The power of it, when it finally bursts forth, is stunning.

The performers are Andalusian Gypsies, a troupe of 21 dancers, singers and guitarists assembled and directed by Claudio Segovia and Hector Orezzoli, the impresarios who mounted the hugely successful "Tango Argentino."

"Pure" is the operative word. The show is not only pure dance and music, but focuses on Flamenco style in its purest manifestation. Flamenco was born among the Gypsies of Spain's Andalusia and has been handed down from generation to generation among them as a treasured cultural legacy. The artists of "Flamenco Puro" are all experienced performers, many of them belonging to families who have cultivated the art across centuries. But they were brought together as a company for the first ,1 time by Segovia and Orezzoli, who were intent on exhibiting Flamenco in the raw, unadulterated form that it still retains among the people who created it.

In contrast to Flamenco productions of a more popularized nature familiar from past touring, there are no fans and no castanets in "Flamenco Puro." Some of the dancers are slender and sleek-bodied, but others are hefty, even bulky; some are young, some are middle-aged or older.

The bodily mass and the years seem to buttress the performers' potency of impact. Flamenco is a febrile, gritty, impassioned art. The words of its songs -- some of them translated in the printed program -- and its wailing melodies speak of rhapsody, but also rage, jealousy, pain and death. The dancing is bitingly percussive, largely a matter of heel stamps abetted by other forms of anatomical rhythm -- hand claps, finger snaps, body slaps. It doesn't aim for prettiness, but for punch, and its performers seek not so much grace as intensity and spiritual rapture.

Similarly, the singing strives for emotional urgency and tempestuousness, not infrequently signaled by a broad, bleating vibrato and raspy croaking, almost as if the singer were choking on feeling. One of the most compelling singers, 68-year old, Cadiz-born Adela Chaqueta, has an alto voice that suggests twice boiled coffee grounds -- dark, grainy, pungent -- and it goes right to the gut. It's the same with the guitar playing, its flaming rivulets of embellishment sometimes converging onto rancid, muddied harmonies.

Each of the performers -- some of whom are known by pet nicknames, like the singer Antonio Nu'nåez, "El Chocolate," or the dancer Antonio Montoya, "El Farruco" -- has a distinctive artistic persona. The 51-year-old "Farruco," beefy in build, almost belligerent in manner, is defiant and imperious. Tall, full-bodied Manuela Carrasco is regal, both in stance and rhythmic phrasing. Eduardo Serrano, "El Guito," draws his slim height up in patrician pride, but there's a tragic undercurrent in the restraint of his style, and a melancholy in his pirouettes.

The program begins and ends with large ensemble numbers ("Bulerias") and shrewdly balances a variety of idioms in between. The program notes, however, could draw clearer distinctions among the types -- to be informed that the Flamenco Tangos are "nomadic like the wind with a high degree of atonal plasticity" doesn't add terribly much to one's understanding. And the program itself would be more effective at somewhat shorter length; there comes a point beyond which one feels under siege. These are, however, relatively minor cavils for a show that is, in sum, both unusual and magnificent.