Nobody likes labels — except maybe critics. ("Nouns are names, and can be libelous," the composer and critic Virgil Thomson once warned.) And we all want to live by Duke Ellington's measure of quality: beyond category. Beyond names and borders, that is, in a post-racial society. And yet, the word "fusion" — at least in music — has a pejorative connotation, suggesting bland pastiche and commercial opportunism.

Composer and saxophonist Phil Scarff has led the Boston band Natraj — who play a CD-release party at Scullers this Wednesday — since 1987, and their most recent couple of albums have displayed the legend "Contemporary jazz with influences from India and Africa." For all that time, Scarff has been trying to have it both ways: creating a music that crosses borders but with clear musical-cultural signifiers, and working in clearly identifiable traditions. Natraj's latest, Song of the Swan (Galloping Goat), shows them working at a peak, creating an integral sound that crosses those borders without a bump.

The initial, title track, with its tamboura drone and percolating tabla, signals "India!" But as the album moves through different regions and tribes of West Africa ("The Ride," with its references to the Dagomba people of Ghana, and "Kpegisu Suite," with rhythms from the Ewe of Ghana and Togo) to the final North Indian raga, you may find yourself losing sight of those borders, and transported to a country that is none other than Natraj's own. The mix of traditional and non-traditional instruments — Western soprano sax and double bass, viola, trap drums, tabla, and bamboo flute — along with smart writing and virtuoso playing creates a fluid cosmopolitan sound without erasing cultural distinctions.

Scarff and percussionist Jerry Leake began playing together in 1986, after Scarff, an ecumenical jazz musician, had come back from his first trip to India. At first, they were interested only in playing North Indian classical music, but then they discovered they had a common background in West African drumming. They decided to combine the three streams — jazz, Indian, African. Leake suggested bassist Mike Rivard. Scarff tried to recruit a tamboura player for the traditional grounding drone figure of Indian music, but as he soon discovered, "No one wants to play just tamboura." So soon the band had a second melody instrument — usually a guitar — and then a second percussionist. By the end of 1994, the personnel had settled: Scarff, Leake, Rivard, violinist/violist Matt Maneri, and drummer Bertram Lehmann, with occasional guests and substitutes. (At Scullers, Scarff, Leake, Rivard, and Lehman will be joined by frequent guest guitarist Prasanna.)

The success of some fusions depends on which part of the equation you favor. For instance, the same night that Natraj play Scullers, the bluegrass banjoist Jayme Stone comes to the Regattabar with a band based on his collaboration with kora player and griot Mansa Sissoko, Africa to Appalachia. This is a perfectly lovely release, but I tend to favor the Africa part, where Stone and his crew subordinate their bluegrass-honed improvisations to Sissoko's playing and singing. Rivard's Club d'Elf (which includes Leake) centers its jammy sensibility on Moroccan music and Jamaican dub. On his new Cubist (Rhombus Publishing), Leake, playing with various studio configurations rather than a working band, is happy to assemble a track-by-track mosaic (as implied by the album title), from jazz-rock guitar over Turkish music (with Randy Roos and Will Graef) to African drums with jazz horns (arranged by Ken Schaphorst). Meanwhile, the jazz guitarist Julian Lage — who's equally drawn to bluegrass and classical — is with his quintet creating a sui generis fusion that lives pretty much in his head and those of his four bandmates.

Song of the Swan owes its unity to the long-time relationships of the musicians and to a bedrock of a shared jazz sensibility ("jazz with influences . . . "). "By this point, I'm playing to everyone's strengths," Scarff tells me when we get together for tea in Inman Square. "Steve Gorn [guesting on soprano and bamboo flute] on the Hindustani material — especially since he toured with us playing that material — and Matt on the African pieces." The latter, with their freer harmonic and rhythmic schemes, suit Maneri's free-jazz aptitude. Another guest, V.K. Raman, joins with bamboo flute on the South Indian raga-based title track, which is from the Carnatic tradition. "Raman is a fantastic Carnatic musician," says Scarff. "It's this nine-beat rhythm — 2 + 2 + 2 + 3 — but for him it's like playing 4/4 swing."

Speaking of which: "Bageshri-Bageshwari," with Scarff and Gorn on soprano, conjures Coltrane swing. "For some reason, 'Bageshri' [a classic northern raga] feels good in swing — I don't know why."

Of course, ever since Coltrane first incorporated some of what he'd heard Ravi Shankar playing, Indian music — with its complex grooves and free-flying scalar melodic improvisations — has been part of the jazz language. And over the past five years, young South Asian–American musicians like Vijay Iyer, Rudresh Mahanthappa, and Rez Abbasi have been redefining the fusion of jazz with music of the Subcontinent.

"What's cool about this is that everyone has his own approach," says Scarff. "It's still all so new that there's not much of a tradition to fall back on, like, 'Okay, let's learn bebop,' and then let's learn this or that. So everybody's inventing their own way of doing this." Still, he allows, when he's listening to Mahanthappa, a Coloradan who's studied in Southern India, he's perplexed. "He's a great player, but it's not obvious to me what he's drawing on from Carnatic music. Which isn't to say that he's not doing it, and it's not great, but sometimes I just don't quite get it."

I wonder whether that isn't the point. In some of the most beautiful moments of Song of the Swan — the overlapping improvised lines of Scarff's soprano and Gorn's flute in "Raga Ahir Bhairav," or the free-time floating drones and twining melodies of viola, soprano sax, and bass in the midst of "The Ride" — genre distinctions dissolve into nameless pleasure. But maybe I'm just hearing it all as jazz.