POP MUSIC : Who’ll Wear the Mantle of the Dead? : The scene looks familiar, but those aren’t Deadheads--they’re Phish Heads and fans of other jam-happy bands proudly embracing the Dead’s legacy of musical improvisation and free-spirited community.

It’s a familiar rock ‘n’ roll scene outside the Greek Theatre as hundreds of eager fans mill about in the crisp night air, hoping to score a ticket to a sold-out show.

The hair tends to be long and the shirts tie-dyed. Hacky Sacks are being kneed and toed, and handicrafts are peddled. The rhythms of impromptu drum circles energize the atmosphere--which is thick with the smell of pot and incense.

These are the same sights, sounds, smells and hopes that have surrounded innumerable Grateful Dead shows since the late ‘60s. Deadheads made each concert a communal, psychedelic event, often traveling with the band from city to city and show to show.

But the headliner is not the Dead, it’s Phish, the Vermont-based quartet that during the last decade has built its own group of remarkably dedicated fans--called, of course, Phish Heads.

Because of the band’s penchant for heady improvisation, its disregard for music industry business as usual and its wildly devoted fans, Phish is one band that has been often cited as an affirmative answer as rock fans and industry observers begin to wonder: Can anybody ever replace the Grateful Dead?

Of course there won’t ever be another Grateful Dead, just as there won’t be another Beatles. But with the future of America’s foremost psychedelic institution uncertain after the death in August of guitarist Jerry Garcia, a thriving group of younger, Dead-influenced bands is carrying on the free-spirited philosophy and the sense of community that surrounded the Dead.

Along with Phish, the bands most often identified with this informal movement include Blues Traveler, the Spin Doctors, Widespread Panic and the Dave Matthews Band.

There are some clear signs of the Dead’s musical influence in the work of all of these bands, but each has also managed to develop its own distinctive sound and its own set of devoted fans. Perhaps the strongest link between these bands and the Dead is a love of touring and live performance.

That love has turned into big business. Phish, for instance, grossed more than $10 million on a 99-show tour last year.

Many of those Phish tickets were undoubtedly bought by some fans who would consider themselves both Phish Heads and Deadheads, but it would be wrong to assume that the bands’ fans and music are interchangeable.

“For us first-generation [Dead] fans, the Dead were the backdrop for everything important in our lives over the last 30 years,” says Toni A. Brown, publisher and editorial director of Relix magazine, which for two decades has chronicled the Grateful Dead phenomenon.

“Phish or Blues Traveler won’t replace the Dead. But using the Dead as a jumping-off point, they’re taking the music to an even higher level. And that celebration of music is definitely worth being a part of.”

The members of Phish have heard themselves being compared to the Dead since they began playing together in the mid-’80s, but they are understandably uneasy with the notion of being seen as the heir apparent.

Still, they freely admit their fondness for the Dead’s music and its influence.

“The Dead were hugely important to American music,” says Trey Anastasio, Phish’s guitarist, in an interview before the Greek show. “They showed that rock ‘n’ roll music could be used as a builder of community and that it could offer a journey into some kind of dreamland that the band and an audience could share. That’s an approach that Phish has definitely embraced.”

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From the first ringing note to the last crescendo three hours later at the Greek Theatre show, the crowd is on its feet, with hundreds dancing in the peculiar boneless fashion that has possessed fans of the Dead for 30 years. As recognizable songs emerge from surging improvisations, applause builds and the dancing becomes even more frantic.

Phish never plays the same show twice, and much excited fan discussion before and after the show centers on the performance of rarely heard Phish songs or particularly striking outside material. This night, fans get a barbershop rendition of “Sweet Adeline” and a soaring, set-ending version of the Beatles’ “A Day in the Life.”

Since the group’s humble beginnings playing happy-hour gigs in Vermont taverns, the members of Phish have mainly concerned themselves with putting on a live show that would speak to whatever audience they could play for.

Drawing from influences such as King Crimson, Frank Zappa and Sun Ra as well as the Dead, they have forged a style that relies on complex song structure, superior musicianship and the organized chaos of group improvisation. They have also eschewed any standard commercial considerations of the music biz, instead taking a grass-roots approach and winning fans one van tour at a time.

After seven years on the road, the vans have blossomed into deluxe coaches, the band is flourishing, and all that mileage is starting to pay off. Last year’s album “Hoist”--the band’s fifth--sold 250,000 copies and got the band its first radio exposure. This year’s concert album, “A Live One,” broke into the Top 20 on the national charts.

A Phish newsletter goes out five times a year to 85,000 fans. And out in cyberspace, a site on the Internet ( Phish.Net , of course) has generated nearly 100,000 pages of text in four years.

Fan devotion is another of the strong similarities between Phish and the Grateful Dead. But guitarist Anastasio quickly points out that Phish should not be looked to as a Dead replacement for grieving Deadheads.

“If people are coming to see us to mourn the Dead--to fill that space--they’re only going to be disappointed,” he says. “It’s not the same. It’s like losing someone you’re in love with and then trying to find that same love with somebody new. You can’t make that kind of emotional connection happen instantly.”

Director Andrew Behar captured the Deadhead scene around one of the Dead’s final Garcia-led tours in his road documentary “Tie-Died: Rock ‘n’ Roll’s Most Deadicated Fans.” He agrees that those fans may have a hard time transferring their affections to a new band.

“I did hear a lot of positive talk about Phish and Blues Traveler, but when I asked people what they would do if the Dead stopped touring, they really didn’t know,” Behar says. “Some said it would be time to go back to ‘normal life.’ I didn’t get the impression that they could just slip into the family of Phish fans.”

There are a few direct connections between the members of Phish--Anastasio, bassist Mike Gordon, keyboardist Page McConnell and drummer Jon Fishman--and the Dead. Gordon uses bass speakers that once belonged to the Dead’s Phil Lesh, and Anastasio credits a long-ago Dead show in Hartford, Conn., as a pivotal event.

“I’d say it changed my life,” he says. “I felt so hooked up to the music--the communication was amazing. That really woke me up.”

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The Dead-inspired jam ethic has been communicated strongly over the last four summers during the H.O.R.D.E. tours, which began in 1992 with a cast featuring Phish, Blues Traveler, the Spin Doctors and Widespread Panic. This year’s lineup, which featured Blues Traveler and the Black Crowes, among others, was a major summer draw that rivaled the much more heavily hyped Lollapalooza shows.

The H.O.R.D.E. tours not only have helped extend and solidify a national community of fans for these bands but have also served as a celebration of the friendships that exist among these groups.

“We don’t just feel close,” says bassist Dave Schools of the Athens, Ga.-based Widespread Panic. “We’re family . We brought Phish and Blues Traveler to the South, and they brought us up North. We might hate being lumped together, because we all like to see ourselves as unique, but we are a big old family.”

Singer Chris Barron of the Spin Doctors was kicked out of an early lineup of Blues Traveler but now considers the members of that band and most of the H.O.R.D.E. acts to be buddies rather than rivals.

“One of the things that marks this scene is a feeling of camaraderie rather than competition,” he says. “I don’t think anybody’s muttering obscenities when one of the other bands does well.”

There’s been plenty not to mutter about lately for the family of jammers. Both Blues Traveler’s “Four” and the Dave Matthews Band’s “Under the Table and Dreaming” have been Top 10 albums--a surprising show of mainstream strength for groups that have valued live performance much more highly than chart performance and radio play.

“The one thing these bands pretty much have had in common is that they’ve been ignored by radio because they didn’t fit any formats,” says Dave Frey, Blues Traveler’s manager and a co-organizer of the H.O.R.D.E. shows. “That makes playing live what it’s all about for all of them. And that’s something the Dead truly pioneered.”

The Virginia-based Dave Matthews Band broke through this year after three years of constant work on the road. Matthews wants to emphasize that success has been a natural outgrowth of the music and the devotion to touring, not the result of any nefarious collaborations.

“There’s a community of bands, but not a conspiracy of bands,” he says, chuckling. “There are no meetings at the docks and no secret handshakes. There just happen to be a lot of bands right now that really believe in the power of live music and who make sure that they have a great time every time they play and let that fun spread to the crowd. I’m happy to be included in that group, especially if it means we’re helping to carry on some of the spirit of the Dead.”

Matthews only recently became aware of the power of that spirit--the first time the singer-guitarist saw a Dead show was when his band opened for Garcia & Co. in Las Vegas in May. “It was awesome. We felt very lucky. The Deadheads were really good to us, and you could tell they’d been treated very generously and lovingly by the Dead.”

The jam-band family also includes some groups that at first listen might seem to have very little to do with the Dead, such as this year’s H.O.R.D.E. co-headliners the Black Crowes, whose bluesy, rootsy sound is often likened to that of the early Rolling Stones.

“I know that for a lot of people we’re the most unlikely band to be drawing those kind of fans,” says Crowes singer Chris Robinson. “But when I started going to as many Dead shows as I could, it hit me that the Deadheads loved the Grateful Dead because the band was steeped in American music and they made it their own. The Black Crowes work with some different roots, but we’re also steeped in traditional music that we want to make our own.

“The strange thing is that since Jerry died I don’t think any of us have played a note of music the same. There’s a space there. We’ve all got to give a little more to fill it up.”

The music that fills that space is being readily embraced by many who love the music of the Dead, even as they come to terms with the end of an era. At Relix, Toni Brown says her Dead-inspired magazine has now taken on the task of introducing Dead fans to the bands that may carry on some of its spirit.

“I don’t think I ever really considered my job important until Jerry died,” she says. “But all of a sudden Relix has become a place for people to turn to for alternatives, and we’re doing better than we’ve ever done. We had some of the first articles on Phish and Blues Traveler and Widespread Panic and many others, and now it’s even more important to let people know that these bands are out there, and that they’ve grown out of a shared culture.”

Musically, the most distinctive part of that shared culture is the art of improvisation: the jam. While each of the jam bands has its own approach to playing, they are united in the belief that inspired music can blossom spontaneously if the players and the audience allow it to happen.

As was often the case at Dead shows, not every spontaneous moment is a golden one. But the jam bands are after the thrill of exhilarating musical surprises, and it is in those moments of surprise that a piece of the Grateful Dead’s legacy is carried forward.

Before going onstage at the Greek, Phish’s Gordon describes the joy of a stirring musical jam.

“Improvisation at its best is better than any kind of rush,” he says. “You hit the right groove and mood and the whole environment shifts. You just get to the point where you feel like you’re in a better world, and you’ve gotten there simply through music.”