The webcam is ready. Security has been alerted. The rope lines are up. And, already, hundreds of people are gathering.

All of this is over a plant. That stinks. Really stinks.

The titan arum, which boasts Earth's largest and most putrid-smelling flower, will bloom in the U.S. Botanic Garden sometime this weekend. Its cult following has made it the rock star of the botanical world.

"I had to come -- just to say I saw it, you know? I want to be able to say I was there," said Rene Carson, a middle school science teacher from Little Rock, after looking at the four-foot green-and-purple flower, still furled tight.

Botanists on hand for the event -- only the second time the titan arum has bloomed here -- predict that the 24-to-48-hour bloom could come soon. The voice mail alerts from the Botanic Garden are changing hourly. Yesterday afternoon, the bulletin board predicting the projected bloom date simply said: ANYTIME!!!!!

"I know it's going to bloom as soon as I leave," said John J. Clark, retired director of transportation for Loudoun County who traveled from Leesburg yesterday just to look. "It's amazing to see something that is so rare. Maybe I'll come back."

The plant is more commonly known as the corpse flower because of its odor. "It's something like a dead rat. You ever had one of those in your house?" asked W. John Kress, chairman of the botany department for the Smithsonian Institution's National Museum of Natural History. A woman standing nearby responded: "In D.C.? Yeah, I've smelled that."

Kress proudly stood by the titan arum yesterday in the Botanic Garden's muggy conservatory, whisking sweat from his hairline with his thumb. He leaned close and swept the plant's aroma toward his nose. "Not yet" was the verdict.

Some of the nation's top botanists began taking turns Thursday standing watch over the flower, answering questions and handing out fliers and photos about the lore and oddity of the plant. The last bloom in the District was a different plant, two years ago, when about 10,000 people lined up around the Botanic Garden's building on the Mall to see it.

This plant has not bloomed for 10 years, making the prospect of a bloom an exhilarating event in the botanical world.

The tall, green bean-looking tower that juts from the soil and is called the spadix was 10.5 inches high Oct. 12. Yesterday, it was 51 inches tall, and the cabbage leaf-like shawl wrapped tight around the spadix was just beginning to unfurl, showing hints of the seductive hue inside.

When it blooms, that shawl -- called the spathe -- opens, and its smell mimics the scent of rotten meat to attract carrion and dung beetles to help with pollination.

"We don't have any of those here, the beetles," said Dan Nicolson, curator for the Smithsonian's botany department. "We're going to try and do it artificially" by hand, he said. "Um, meaning, it looks like I'm the great pollinator."

The U.S. Botanic Garden, at 100 Maryland Ave. SW, will be open from 10 a.m. to 5 p.m. today and until 7 p.m. tomorrow. The webcam and more information are at, or call 202-225-8333.

As the blossom on the titan arum begins to unfold, one visitor from Arkansas said she "had to come -- just to say I saw it."