A Mass for missing mushroom expert Hildegard Hendrickson, 79, will be held next week at Seattle University as family, friends and former colleagues struggle with the lack of information about what happened to the popular former educator.

“It’s a delicate situation. This is not a funeral,” said the Rev. Peter Ely, SU’s vice president for mission and ministry. “It’s a way for us to come together and pray for her … a way for us to support the family in prayer.”

Hendrickson was last seen June 8 when she headed out alone on what was planned as a day hike to search for mushrooms in a mountainous area north of Lake Wenatchee in Chelan County.

An extensive search turned up no sign of the missing woman, prompting some who know her to wonder if she was the victim of foul play. Chelan County Sheriff Brian Burnett has said all possible scenarios are being explored.

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Hendrickson taught at SU from 1967 to 1996 and served as chair of its department of economics and finance.

The Mass at Seattle U. follows a prayer vigil held Sunday evening at Our Lady of the Lake Catholic Church, a service that prompted both smiles and tears.

“It was very nicely done … trying to find the balance between hope and despair,” said John Eshelman, a retired Seattle University professor and administrator who works in the university’s development office.

Eshelman said Hendrickson could be brash, bold and, as a speaker at Sunday’s service said, “feisty,” but her direct, energetic approach earned admiration.

“She was always a favorite of the students,” he said. “She wasn’t easy; she was tough, but they really appreciated her.”

Eshelman said his longtime friend was a pioneer, becoming one of the first women to receive a doctorate in business administration from the University of Washington.

Her disappearance stunned many who know her through the Puget Sound Mycological Society, a group of mushroom enthusiasts she joined in 1972.

Hendrickson, an expert in mushroom identification, held free weekly sessions at the Center for Urban Horticulture, in which she would identify mushrooms and help people ensure that any mushrooms they planned to eat were safe.

Dozens of members of the group helped in the search for Hendrickson, whose car was found, unlocked, at a trailhead, three days after her planned hike. Although she often hiked alone, members of the mushroom-hunting club said she seldom went far from her car.

The Mycological Society also recently held a prayer vigil for Hendrickson. About 120 attended, said the group’s president, Marian Maxwell, a longtime friend of Hendrickson’s.

“The hardest thing is not knowing anything,” she said. “There’s just this void of information.”

Hendrickson, whose husband died in 2001, has two sons, both in the Seattle area.

Jack Broom: jbroom@seattletimes.com; 206-464-2222