It's a necessary strategy as more competitors look to older women to boost sales as malls become overrun with teen retailers, including Hot Topic and Abercrombie & Fitch. Even companies that indulge youth are growing up: Gap Inc. launched a new chain, Forth & Towne, last year aimed at women over 35. Children's clothier Gymboree Corp. started Janeville in 2004 to cater to older women; today it has 16 stores, including one at Chestnut Hill's Atrium Mall. And teen chain American Eagle recently announced it will open the first four stores of its new Martin + Osa brand targeting older women this fall.

But this market isn't a sure bet, retail analysts say, especially for companies that have little experience or success with this age group. The Gap, for example, holds significant market share among younger demographics, but has less than 3 percent of the 35 and older crowd. Women may be less finicky than teens in terms of following trends, but they are loyal customers. When shops fail to deliver, it's hard to bring these women back.

For Talbots and J. Jill, which have long served older women, the challenges will be to bring in new customers as rivals crowd the market, and to adapt to the changing tastes of this generation. Teamed up, the two South Shore companies would have 1,283 stores and an annual revenue of about $2.3 billion. The acquisition represents Talbots' first since it opened in 1947. If the deal is approved, the combined companies would overtake Ann Taylor, which had about $2 billion in sales last year, and widen their lead over Chico's, which had about $1.4 billion in sales last year, according to analysts.

To accommodate the evolving tastes of women over 35, stores like Talbots say they must delicately introduce fashionable merchandise without turning off core customers who depend on them for classic styles. Talbots learned its lesson in 1997 when the company strayed from its tailored look and tried to channel youth with trendy short skirts and high slits. The company had its worst year ever, according to spokeswoman Margery Myers, but now Talbots knows to offer items that are stylish but forgiving for what nature does to mature bodies.

Take Talbots' "bling jeans" — denim embellished with rhinestones — which until recently would have been unheard of at the conservative chain. The jeans are now among the company's best selling pants with a contoured waistband that dips lower in the front and curves in the back so that a woman with hips can move, bend and sit comfortably.

"Our customer wants fashion, but fashion that fits her," said Talbots chief executive Arnold Zetcher. "She views herself as younger — the 50-year-old woman today thinks of herself as 40."