The recombinant sounds of hip-hop change so quickly nowadays that you can almost see it happening in real time. This hyper-rapid-evolution is observable in the music of Dizzee Rascal, the poster boy and ambassador for the fledgling yet ubiquitous British hip-hop style known as grime, as he wends his way through the United States on his first solo tour.

America was first introduced to the grime sound with Dizzee’s debut album “Boy in da Corner,” released stateside in January 2004. Full of spare, almost oriental beats, deep bass, and dense, staccato rhymes, it distinguished itself from homegrown hip-hop while still paying respect to it. “Showtime,” Dizzee’s follow-up, arrived on American shores a short eight months later. Already the melodies were more pronounced, as though extending an inviting hand to American listeners.

But U.S. hip-hop operates by collaboration and fiat; few succeed here with out the imprimatur of already established stars. Dizzee has played shows with both Jay-Z and the Neptunes, but he has yet to record any high-profile, breakthrough collaborations that would signal the blessing of America’s hip-hop establishment.

Instead, grime is filtering in little by little. Last month, “Run the Road,” a compilation released on the tastemaker label Vice, introduced American listeners to a whole new cast of grime MCs and producers. And Dizzee recently supplied a remix of “Hell Yes,” renamed “Fax Machine Anthem,” for the deluxe edition of Beck’s new album “Guero.” It reconstructs the song using the sonic raw material of grime.

However, history may well judge Dizzee’s current tour as the event that cemented the relationship between grime and America. Like the Sex Pistols’ notorious first tour of the States in 1978 (which was concentrated, of all places, in the South), Dizzee is bringing his radically foreign style to out-of-the-way places – Vancouver, British Columbia, Portland and Eugene, Ore., and Salt Lake City, Utah – as well as hiphop hot spots.

When I caught up with the rapper by phone from Houston, he talked enthusiastically about the response at the shows. “I didn’t really know what quite to expect, even though I’ve done shows,” he said. “There’s a lot of energy, people are really getting into it. It feels good because every show feels like the first time.”

Dizzee’s tour arrives at Irving Plaza on April 23, but the smaller stops along the way may prove more interesting and musically fruitful. Dizzee approaches the tour with missionary zeal and the patience of a public school teacher. Traveling with him is DJ Wonder, one of grime’s most respected producers and the man responsible for the beat to Dizzee’s hit “Respect Me.” Wonder opens each show with a 45-minute DJ set he’s touting as a history of grime; he occasionally interrupts the set to offer context and explication.

The cultural exchange program works both ways. Dizzee is immersing himself in the local scenes he visits. During his stay in Houston – whose homegrown chopped-and-screwed sound is on the verge of blowing up with a breakthrough song (“Still Tippin’ ” by Mike Jones) and a flurry of attention from the New York Times and MTV – he took time out to record some tracks with local heroes Bun B and the Grit Boys.

He also made an appearance at the local hip-hop radio show “Damage Control.” (An MP3 of the session is available on the “Damage Control” Web site: www.damagecontrolradio.org/mp3/dizzeeshow3.mp3.) After a short Q & A about the urban music scene in London, Dizzee and the Grit Boys get on the mics. It makes for fascinating listening.

The two styles almost couldn’t be more different. Grime is hyperactive and choppy; Houston is molasses slow. But the rappers complement each other nicely. First they trade freestyle verses over the chopped-and-screwed hits “Still Trippin'” and “South Side.” Dizzee spits four of five words to every one by the Grit Boys. Then they switch it up, flowing over hardcore grime beats supplied by DJ Wonder. This could be a train wreck, and the Grit Boys sound a little baffled at first, but soon find their footing. “I stay on the grind / we call our music gutter / Dizzee say he call his crime, or grime,” raps one of the Grit Boys by way of blessing the union.

There aren’t any Billboard hits coming out of these sessions – not immediately, anyway (there’s no telling what this cross-pollination may ultimately yield). For now, it’s enough to introduce America to Dizzee’s distinctive sound, and immerse Dizzee in the varied sounds of American hip-hop.

Experiences like this have only buoyed Dizzee’s feelings about grime’s prospects in America. “There’s so much hip-hop in America, it’s so big, it’s the home of it,” he said. “There’s so many people doing it, why wouldn’t people want to hear grime?”

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The White Stripes provided a first glimpse of their forthcoming album, “Get Behind Me Satan” (due out June 7 on Third Man/V2/XL Recordings) with the exclusive iTunes release of the song “Blue Orchid” yesterday. Finished just two weeks ago, the song continues Jack White’s fertile mining of the past – albeit a different historical pastiche this time. The guitars sound like neutered cock rock, and Mr. White’s falsetto is pinched into a Prince-like post-disco soul sound. Meg’s drums, meanwhile, still rattle and clang like they’re tumbling down a hill. Like so much else in the White Stripes’s work, it’s a retro sound too big and inventive for the meager label “retro rock.”

Dizzee Rascal will perform at Irving Plaza April 23 at 8 p.m. (17 Irving Plaza, between 15th and 16th Streets, 212-307-7171).