New York fashion runways this week as many designers shed the stiff, formal styles of seasons past.

From established powerhouses such as Badgley Mischka to newcomer Christian Siriano, the spotlight is on evening wear fit for Hollywood stars on red carpets and socialites hosting charity events.

Elegant, easygoing gowns of sleek silk chiffon and draped jersey are showcased in spring and summer 2010 collections by Farah Angsana, Reem Acra, Chado Ralph Rucci, Monique Lhuillier, Narciso Rodriguez, Vivienne Tam and Venexiana by Kati Stern.

"It's become more modern," said stylist Rachel Zoe between shows at New York's Mercedes-Benz Fashion Week. "We've pulled away from the big grand gowns. We're seeing a lot of mermaid silhouettes. It's more fun."

Zoe, known for putting such actresses as Anne Hathaway and Cameron Diaz in haute couture for the Academy Awards, noted a prevalence of short and tea-length dresses.

"It's young and refreshing," she said, especially for "all these young girls with their incredible legs."

But the long gown isn't about to fade away.

Christian Siriano, 23, among the youngest designers on hand this week, showed strapless and one-shoulder gowns in ocean blue, red, coral and blush, some in prints inspired by aerial photographs of Italy's Amalfi coast.

"Take this one," he said, picking up a gown of light, satin-faced chiffon in a blue print. "You get the idea of the water, the rocks and the sand."

Siriano, who shot to fame as a winner on cable television's hit "Project Runway," said licensing deals with Payless and Victoria's Secret give him ample revenue to finance his couture gown and bridal business.

His gowns, made in his Manhattan studio, typically sell for $5,000 to $8,000 each. Badgley Mischka gowns start at $2,500. And Farah Angsana's spring gowns will sell for up to $17,000.

LONG STORY SHORT

Actress Katrina Bowden, 20, of NBC's hit comedy "30 Rock" said she planned to wear a long Siriano gown to the Primetime Emmy Awards this weekend.

"I've worn short, and long is a little more glamorous," she told Reuters."

Hot pink and cherry red silk gowns appeared in the runway show by Badgley Mischka, a couture label founded by Mark Badgley and James Mischka in 1988.

"We were in Palm Beach at the home of some friends, who are from Cuba," Badgley said. "On the walls were pictures of all these beautiful parties from the '50s, the jewels and the vivid colors. We wanted to bring that back."

They, too, mixed long gowns with short cocktail dresses, slouchy evening pants and luncheon suits. "But the gowns are our core business," Badgley said.

The Badgley Mischka customer is "still shopping, just not buying as many," he said. "Instead of buying three, she'll buy one."

Shorter cocktail dresses and evening separates are a nod to changing tastes in the glum economy, noted designer Naeem Khan. He said his sales were off 20 percent to 30 percent in January but have since picked up at such top stores as Neiman Marcus [NMRCUS.UL], Saks Fifth Avenue (SKS.N) and Bergdorf Goodman, which is owned by Neiman Marcus.

But customers such as Wall Street executive Alexandra Lebenthal, who will chair an Alzheimer's Association gala at the Waldorf-Astoria Hotel next month, aren't biting.

For her charity event, she is adapting a gown she already owns. "I'm having some flowers added," to go with the gala's fuchsia color scheme, she said.

Iris Apfel, a couture collector, had a suggestion for designers after catching the Chado Ralph Rucci show. The looks were beautiful but "women of a certain age" want sleeves rather than sleeveless or strapless dresses.

She said she appeared at an event with designer Michael Vollbracht, where women asked him where they could find evening gowns with sleeves.

"He said, 'Well, I think for $15,000, you're entitled to some sleeves,'" she said.

New York Fashion Week runs through Thursday (17 September) night. (Editing by Ellen Wulfhorst and Xavier Briand)