Donald James never tired of mushrooms, sweater vests or knowledge.

A Ph.D. in mathematics, he taught and tutored for decades, including teaching college math at Metro State University as well as working with child refugees from war-torn Eritrea. His grandchildren spent many hours at James' kitchen table, learning to prove the 80 theorems required to pass their 8th-grade math tests.

And when hosting a dinner party — which he often did — James loved nothing more than when a guest could contribute a bit of information he hadn't known.

James, of St. Paul, died July 4 at age 88 of heart failure.

James grew up in Ames, Iowa, where he and his twin brother were local celebrities known as "the James boys." They dressed alike every day from childhood through college at Iowa State University.

He met his wife, Suzanne, when he was an usher at the local movie theater and she was a ticket-taker. The couple moved to the Twin Cities when James took a job at Honeywell, where he managed a group of engineers and software designers who created a laser gyroscope used on the space shuttle.

But this buttoned-up scientist had a goofy side that makes friends and family members laugh to remember it.

"He made up really bad, punny jokes and he wouldn't let them go," said his daughter, Cynthia Murdoch of St. Paul. "We thought they were funny the first time."

A man who knew his style and stuck to it, James had a closet full of sweater vests of every color and wore one nearly every day. And if he wasn't wearing a sweater vest, he was wearing a sweatshirt with a math joke on the front of it. A favorite was "pi a la mode," with the mathematical symbol pi and a scoop of ice cream.

"We all worked so hard to find a good one for Christmas each year for him," Suzanne James said, adding that she may turn his sweatshirt collection into a quilt.

Speaking of Christmas, James had strong views on the proper presentation of gifts.

"He was really precise," Murdoch said. "He could make wrapping a present take an incredibly long amount of time. And if he had striped paper, he liked it to have mitered corners and have all the lines line up perfectly. They were just gorgeous."

James had an almost obsessive love of mushrooms. Whatever amount a recipe called for, he'd double it, and if his wife was cooking a dish without mushrooms, he'd ask if they could add some. One Christmas, he was delighted when his daughter gave him a log impregnated with mushroom spores, allowing him to raise his own fungi in the basement.

At one point, James became intrigued by horse racing and devised a system of betting that included an ever-growing list of variables he'd plug into his formula. He didn't actually bet — he just checked the results from Canterbury Downs in the newspaper to see how he would have done.

The Jameses traveled widely, visiting more than 50 countries. Donald James would plan the itineraries, poring over guidebooks and putting together lists of places to see. And when they returned from their trip, he'd put together a beautiful scrapbook of the voyage, with photos, tickets stubs, programs and other memorabilia.

A lover of music, James and his wife were regulars for decades at concerts by the Minnesota Orchestra and the St. Paul Chamber Orchestra. He played the piano by ear, and each day he'd play a concert for his wife of songs he'd composed in his head.

"I miss that terribly," she said. "I'll never get over missing that. He was quite the guy — really exceptional in many ways."

In addition to his wife and daughter, James is survived by two grandchildren. His son, Christopher, died four years ago. The family plans a private memorial gathering.