THE ROVING EYE.

IT'S late afternoon and your energy is fading as fast as the sunshine. Do you gulp down that 10th cup of Starbucks and risk climbing the walls all night?

Instead, you may want to try a mellower jolt from yerba mate tea, which is enjoying brisk sales at various markets around town.

"Yerba mate is a truly healthful alternative to coffee," says Chris Mann, CEO of Guayaki Sustainable Rain Forest Products Inc., an importer and wholesale distributor of the stuff. "South Americans in Argentina, Paraguay and Uruguay have been drinking this rejuvenating beverage for centuries, relying on its wealth of nutrients to sustain them."

Of course, Angelenos tend to like their hot beverages a bit fancier.

So Mann and other local tea purveyors have come up with such concoctions as the Guayaki Mate Latte, the Guayaki Chai Latte, Cinnamon Bliss and Sweet Sunshine -- enhanced with various organic sweeteners, vanilla soymilk and concentrated extracts.

After all, you wouldn't expect anyone to trade in their cherished double-espresso mocha latte for a simple cup of straight tea, would you?

"It has a nice buzz in a healthy sort of a way, and you can drink a ton of it without climbing the walls at night," says veteran coffee lover Carol Stein.

Fans of yerba mate, or those who are merely curious, can find it at Wild Oats, Whole Foods and Trader Joe's markets. Of course, home sipping isn't always as fun as hanging out in a coffeehouse, but don't despair. Mann's company is planning to open a chain of Guayaki Cafes, with the first one targeted for L.A. next spring.

"The Los Angeles area has been incredibly receptive to the philosophy of a sustainable, environmentally friendly alternative to coffee," says Mann.

So what does Starbucks think of the competition?

Tad Harold, a longtime employee, says: "It will never replace a great cuppa Joe."