It should come as no surprise that Hawaii was an early adherent of dress-down Fridays. Fact is, the movement started there.
"Aloha Friday" was begun some 25 years ago when the state legislature encouraged its constituents to trade business attire for Hawaiian shirts and slacks one day a week.
"Around the late '60s, one of the managers of the Bank of Hawaii helped to start the trend," according to Bart Silberman, national sales manager for Reyn Spooner, a shirtmaker in Kamuela on the Big Island.
"Eventually," he says, "members of the state legislature began wearing their Hawaiian shirts rather than coats and ties when they convened on Fridays. And then the legislature made it official. It was the true predecessor of Casual Friday."
Now the Hawaiian shirt, once a gaudy souvenir for tourists and a badge for geeks, is riding the wave of mainland fashion. New shirts are good. Vintage ones are better. But they must have short sleeves and bright prints of sun-kissed surfers and hula dancers, pineapple plantations and coconut trees.
He says the lobby of the Ritz-Carlton Laguna Niguel halfway between Los Angeles and San Diego is a good place to spot Hawaiian shirts paired with upscale attire, such as a navy tropical-weight Hugo Boss blazer, cream silk and linen trousers and tan woven Cole Haan loafers.
"That look has definitely become an acceptable form of dress for businessmen," according to Mr. Silberman, a former retailer in Newport Beach, Calif.
Well, maybe not all businessmen.
"New York is still very much an upscale coat-and-tie society," he says.
Still, change is coming, according to a co-owner of Radio Hula, an emporium of Polynesian collectibles in New York City's trendy SoHo neighborhood.
"In the last three years, our audience has grown to include a lot of businessmen," Janu Cassidy says, though he doesn't attribute a two-fold sales increase entirely to casual Fridays. Rather, he says, his customers "tend to be a lot more conservative during the week and want a little more action in their wardrobe on the weekend."
What Radio Hula sells are silk reproduction shirts by Avanti at $85, and in cotton-rayon by Quicksilver, $69 each.
As Hawaiian shirts drift into mainstream, Gant has one with tropical flowers and palm leaves in linen and cotton, $56, and Nautica's is linen and rayon with sailboats and huts, $79, in khaki, faded denim and green tones. Chaps by Ralph Lauren goes corporate with a cotton button-down palm-leaf print in off-white, tan and navy, $46.
For women, Carole Little surfs the tropics with a bevy of rayon shirts from three groups - Polynesian Postcard, Heatwave and Tropical Lagoon - at $68 to $88 apiece.
For chic on the cheap, Target offers a $13 men's cotton shirt by Great Land in a tropical print. Rayon shirts at Mervyn's, by High Sierra, are $24, or sale-priced at $14.
Some manufacturers hire artists to draw designs. Others download computer software for copies of old prints. Whatever the source, Aloha shirts have the same silhouette as a short-sleeve pajama top.
Reyn Spooner, however, has added a cotton button-down number to its line of rayon print shirts, $65 to $75, which explains why some call the company the Brooks Brothers of the Pacific.
Thrift stores are a good bet for tacky but trendy Hawaiian shirts in '60s polyester. At some vintage boutiques, happy little rayons or cottons from the '50s run about $25.
But it's the more unusual oldies that catch the eye of the aficionado. Shirts that cost $1 a half-century ago now can go into four figures. And islanders who once would never have worn a shirt made for tourists are among the buyers.
"Now they look back, and it's such an ancestral thing, so they're paying the big price, too," according to Ronnie Crawford, owner of American Vogue and American Aces, vintage stores in Denver.
Among Mr. Crawford's treasures, for $1,000, is a shirt like the one worn by Montgomery Clift in his death scene in From Here to Eternity.
Mr. Silberman, who has some 450 old shirts in his personal collection, says some of the most avid collectors are from Japan, where "Hawaiian shirts represent the true form of vintage Americana."
Prices vary with the geography. A 1950s rayon shirt in a vintage clothing store on the East Coast will cost about $100, he says. The same shirt might be $250 in Dallas or Chicago and $500 in California. In Hawaii, with a huge influx of Japanese tourists, stores that specialize in vintage shirts might sell it for $1,000.
Mr. Silberman isn't alone in his knowledge or in his quest.
"Just in Hawaii," he says, "there are 50 to 100 of us here turning over every rock looking for old shirts."
Among the most desirable are original hand-screened silks and rayons. If you do your homework, the label can help you date the shirt. Also, look for coconut buttons and carefully constructed matched pockets with no interruption in the pattern. Flap pockets are more unusual, as are long sleeves.
"What's very scarce and highly desirable," Mr. Crawford says, "is a woman's blouse with darts and little cotton shoulder pads, fitted at the waist."