The anticipated event had not yet occurred by Wednesday evening, though faint wisps of stink emanated from the closed petals. The enormous, rarely cultivated corpse flower, a native of the Sumatran rain forest, stood poised like a 4-foot upside-down umbrella, still closed and hoarding its appalling perfume.

"It's like waiting for a pregnant lady," Ernesto Sandoval, caretaker of the plant – the Amorphophallus titanum, or more informally the titan – said affectionately. The director of the UC Davis Botanical Conservatory couldn't be sure when the great flower would unfurl, but the past four blooms had occurred in the afternoon.

He has known the corpse flower since its arrival, as a seed, in 1996. He said the timing draws insects in to the open flower in the evening, to stay the night deep in the flower's ruffled collar.

The plant does not eat insects. "There are some flowers that trap insects – for a one-night stand," said Sandoval.

Corpse flower, carrion flower, bunga bangkai in Indonesian – the plant's common names conjure its smell. The flower finally opened Thursday afternoon, releasing a heat-propelled, meaty odor as repellent to humans as it is attractive to the plant's insect pollinators.

But it had attracted quite a crowd by Friday morning.

Visitor Laurie Stillman had anticipated a more overwhelming smell. "Not as smelly," echoed her son Jordan.

"But it's bigger than you are, huh?" asked his mom. The little boy solemnly agreed. The two were on an odoriferous adventure.

"We're having a stinky day," said Stillman. Next stop: the dump.

Seventeen hours after the big opening, the titan's stink had mellowed.

"It was really, really stinky last night," said Connor Brand, back with his grandpa for another whiff. The greenhouse stayed open until midnight Thursday so that visitors could admire the titan at its most aromatic.

The plant attracts carrion-eating flies and beetles with the smell of death, tricking them into serving as pollen-bearers.

"The insects get nothing out of it," said Sandoval. "We all know relationships like that!" The smell fades as the titan begins releasing pollen from the tall central column, the spadix.

"It has to stop smelling so attractive, so that the flies will leave," said Sandoval. The staging discourages self-pollination. When insects move on, they carry away pollen, potentially to fertilize the flowers of another titan.

Sandoval beckoned some of the many visiting kids to touch the spadix, and squeeze it to feel the hollow space inside.

Amanda Dixon said it felt a little bit sticky.

"And rough!" added her friend Vivian Gallegos. They agreed that their fingers smelled nasty, an icky souvenir to take home.

The huge, deep red "petals" are actually just a collar. Hundreds of tiny flowers cluster inside, at the base of the spadix. The pollen-producing male flowers sit just above the female flowers, which grow the seeds.

As in the wild, in the conservatory the titan blooms only every few years, when it has stored enough energy in its corm, or tuber, for the undertaking. The plant burns stored carbohydrates, heating up the spadix close to body temperature. The heat helps get the heavy, oily stink compounds airborne. That takes a lot of calories.

Dixon took a picture of Gallegos and the titan, but no device could capture the remarkable smell. Their parental escort had already mentioned disinfectant wipes waiting in the car.

The flowering is an ephemeral event. The bloom of the corpse flower dies after its second day.

UC DAVIS

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