The marketplace

Fern is its symbolic flower, butcher block its tree, and brick its ''soil.'' The territory so symbolized is, in fact, an urban landmark: It is the marketplace, the collection of shops sheltered under one roof, decorated with fern, butcher block, and brick, and fitted out with the goodies that make America drool.

This consumer ''state'' of getting and spending, modeled on Boston's Faneuil Hall Marketplace, is a success story. An in-town amusement park that boasts more visitors than Disneyland, Faneuil Hall is clearly an architectural and commercial achievement that is emulated everywhere.

Clones appear and even a splendid text on the two centuries-old form called ''Arcades'' is reissued ($50, MIT Press).

Built at Baltimore's Harborplace or in Georgetown Park, in Washington, D.C., and planned for South Street in New York and Portland, Maine's, waterfront, these places are breathlessly upscale but universally, trendily appealing.

They are one of the few prospering forms of architecture in tough times. Or, as Jeffrey Blydenburgh, the architect whose firm refurbished Davol Square, which opened here last month, puts it: ''Everything except markets is a hard-time business.''

Although surrounded by decrepit buildings when they open and cut into neighborhoods of industrial blight or marginal commercial life, marketplaces mark a revival. More than a revival: gentrification. Or so critics in Portland and New York worry when they consider what such flourishing zones might do to the ''genuine'' neighborhoods they replace or adjoin.

The concern is real, but for Providence, one of the most laggard of the nitty-gritty cities of New England, the openings, first of the Arcade downtown two years ago and now Davol Square, are less ambivalent; and they're especially instructive in showing the range of these architectural purveyors of quiches and quirkery.

The downtown Arcade, originally built in 1828, winner of several architectural awards in the two years since it was redone by Irving B. Haynes & Associates, bills itself as ''the first indoor shopping mall constructed in this country.'' The kinship cannot be denied.

On three floors enclosing 40,000 square feet, the structure behind the looming 12- to 15-ton Greek Revival columns is both a tenant of and retreat from downtown.

Straight, not meandering, and uniformly chopped into $3 million worth of colonialized openings, the Arcade produces the claustrophobia of a mall and the uniformity that designers condemn as ''suburban.'' It is adorned with wrought-iron trim and flags, and is bustling with life. More important, it partakes of the vivacity praised as urban. In short, it is both an urban miracle and a suburban mall.

Davol Square, less arresting in its original outlines - a gutted medical supply factory - is more striking in its contemporary enhancement. Though its abundant parking and eight-minute walking distance from downtown define it as a suburban mall, its grandiose size (a chain of buildings amounting to 115,000 square feet of restaurants, shops, offices, and function rooms) somehow makes the complex a more citified space.

Above all, Davol Square stands out from the glut of markets for its glimpse and its deep breath of the outside world. The neighborhood is visible through windows and accessible through doors.

Architects Beckman, Blydenburgh & Associates (the project manager was Alfred Oakes) have supplemented the staple Galleria with cutouts to the outside world through windows on the street.

Combined with a zest for the details, a strong hand in designing shops, and buildings wayward enough to allow wandering, it has a human irregularity. Davol Square avoids some of the mall's dense and overwhelming materialism which gives shoppers a sense that they are smothering in an overenchanted forest of Paddington bears.

High-tech touches also relieve the tedium of the idiom. Steel bridges crossing the 260-foot-long Galleria enliven the interior beneath an energy-efficient Kalwall translucent roof.

Glass bays zigzag in and out of the shops, giving the requisite sparkle.

Despite restaurants with arch labels (''ahhh'' to name one the Down-and-Out Sprout!), the linkage to workaday life comes in the form of the C.E. Maguire offices adjoining and overlooking the market. The engineers who designed their 40,000 square feet of connected space added an agreeable reality gauge, visible through the brick arched windows that line the Galleria.

Some of the architects' heroics (or architectural sit-ups) don't quite work. The cable trays holding power lines lack grace; the slick exterior of the top-floor addition jars. But by and large the details - from the firm's light fixtures to their shifts in colors, and the stuccolike Dryvit classical facade on the top floor to the mahogany-framed windows that actually open, and the bold exterior tubing - all these respect the old architecture without boring those who long for the new.

In short, the architects, with their consumer haven, have observed and enlivened a neighborhood that never even had a name. Yet the transformation of this nameless place in Providence through a market does not alter the issues that other marketmakers face.

At South Street in Manhattan and at the Portland waterfront, the transformers face the opposition of those who prefer down-at-the-heels to high-platform posh. Especially in New York, Rouse Associates, once praised for the clean sweep at Faneuil Hall Marketplace, are criticized for plans (here, as there, by architects Benjamin A. Thompson Associates) that would replace fishmongers' sawdust with humus, the smell of cod with the aroma of David's cookies.

The question for architects and urbanists, unresolved in Davol Square, remains: Is the marketplace to be just one more mall in the city, an island that prettifies but does not connect?

This sometime shopper and most times urbanist can only come down on the side of those who find romance in the seedy (even if she has to take her tea with crullers, not croissants). But is it 1980s snobbishness to prefer proud poverty to proud popovers? Hasn't Faneuil Hall, not to mention the more locally run Harborplace in Baltimore, brought new citygoers?

Those who want to keep their cities ''honest'' cannot forget the opposite kinds of complaints from just a decade ago:

''The only way to get the human contact and the variety of food back, and all the love and care and wisdom about individual foods which shopkeepers who know what they are selling can bring to it,'' Christopher Alexander wrote in ''A Pattern Language,'' ''is to create those markets once again in which individual owners sell different goods from tiny stalls, under a common roof.''

The marketplace does that. In the midst of the mega-structuring of America, it pays attention to the minute.

But whether this hybrid can retain the old and market the ordinary along with the coy in urban commerce may be the most vital urban-suburban issue of our day.