Art doesn't grow just in Manhattan -- take Boston for instance . . .

Rumors to the contrary, the best in American art doesm generally end up in New York. Not all, I'll admit, but certainly a great deal of it. New York, after all, is still the national art center. Most of America's major galleries are there, as well as some of its most important museums. A large number of its most influential critics, curators, and dealers operate in and around Manhattan. And when it comes to a centralized art community, there is nothing comparable elsewhere in the United States to what exists in SoHo and its environs, and along Madison Avenue and 57th Street.

All this, of course, makes it very easy for those who live and work in New York to assume that whatever happens in art on the other side of the Hudson River is of little importance - and to look upon everyone not actively connected with the New York art scene as provincial and lacking in sophistication.

That just isn't true, as I've been discovering with increasing frequency while traveling around the country. New York may be the professional and commercial center for American art, but it is by no means its creative heart. It's much too artificial for that, too hungry for what is created elsewhere. It may still be the final arbiter in matters of reputation and career, but it depends more and more on what the rest of the country sends its way.

I'm reminded of this every time I am in Boston, a city that for the past three centuries has produced more than its share of important American art. And in a strictly contemporary sense, I am reminded of it every time I visit the Nielsen Gallery, at 179 Newbury Street here.

I always approach the Nielsen Gallery with a pleasant sense of anticipation - and leave it knowing I've seen some good art. There have, of course, been times when I couldn't respond to some of the works on view, but that has never lessened my respect for the gallery, its art, and its owner-director, Nina Nielsen.

The Nielsen was founded in 1963 as a print gallery, and part of its lower level is still set aside for the display of master prints. (At the time of my most recent visit, I noticed some excellent prints by Kollwitz, Rouault, Beckmann, and Heckel.) But it is as a gallery of contemporary painting that the Nielsen has made its real mark, and is best known throughout the US.

The group show I saw there recently more than upheld its reputation. Gregory Amenoff's two paintings, not surprisingly, stole the show, and proved once again that he is a painter of both passion and sensibility. Also outstanding were Paul Rotterdam's enigmatic ''Substance 398'' and Neill Fearnley's magical ''Blues for the Abstract Truth.'' (Fearnley's name immediately went into my little black book of exceptionally promising younger artists.)

And I was intrigued by Jonathan Imber's ''Portraits of Philip Guston in Overcoat.'' I like what Imber is attempting, even though I find this particular work somewhat weakened by academic overtones. For all its power, it is a bit banal.

In all, an excellent group show. It is scheduled to be followed by an exhibition of paintings by e. e. cummings on Feb. 11.