On a Monday morning in May, during his usual walk around the University of Colorado greenhouse he manages, John Clark spotted something strange.

“Like this giant, green thumb sticking up in the air,” he recalled.

He walked around a corner and spotted another.

It was agave — the succulent very rarely seen around Boulder and the state beyond. Not blue agave, the more prolific type associated with tequila, but a different, more elusive desert species that would tower above 14 feet and burst with bright, yellow flowers.

“It was exciting,” Clark said of the initial discovery. “Certainly, it’s something that doesn’t happen every year.”

It’s something that might happen closer to 30 years. Such is the case with these two agave, which in recent weeks have drawn a steady stream of admirers to the Ecology and Evolutionary Biology Greenhouse on 30th Street in Boulder.

They are a stunning, commanding sight thanks to a man who planted them in the mid-1990s, around the end of his teaching career on campus.

As he laid the seeds back then, Allan Taylor was well aware that he might never see the bloom that would only come after decades of the agave storing energy underground and waiting for the right time to flower and then perish, as the lifecycle goes for the plant commonly called a “century plant.” Of course, the bloom would only come if the agave survived those many years underground in the first place, Taylor knew.

There he was last summer at the greenhouse, 90 years old and breathing with the help of supplemental oxygen, smiling wide at the first agave plant that sprouted.

“He was tickled, so tickled,” said his daughter in Boulder, Yoana Georgis. “He didn’t think it was gonna happen in his lifetime. He was running down the clock.”

Time ran out last December. Taylor died before he could see two more of his agave.

When she got word of them this summer, Georgis was brought to tears.

“I wish he could’ve been able to hang on one more year, because he would’ve gotten to see these two more,” she said. “He would’ve just been thrilled.”

And so the new head-turners in town are bittersweet for Georgis — sweet for what they stand to represent.

“It’s a true living legacy,” she said.

It’s a legacy of a man remembered as a Renaissance man, a linguistics professor whose interests spanned far beyond that field.

As much as Taylor loved language, he loved history. He earned his master’s in archaeology during his CU career that began in the 1960s.

His first degree from the school was in international studies.

“He was Google before Google,” Georgis said. “My siblings and I would ask Dad anything, and he could answer it.”

More than anything, Taylor loved the natural world. He loved the Southwest.

“He was always collecting things,” Georgis said. “On all of our road trips, he always had a wooden box tied to the top of the car. We were always terrified driving with him, because he was watching the side of the road more than he was watching the road.”

Once, closer to home along the Peak to Peak Highway, he spotted yellow on the single tip of an evergreen branch. The discovery led to him propagating what would be called the Taylor’s Sunburst, now a sought-after pine for landscaping.

It is but one industry special with Taylor’s name on it. His yard in Boulder became an ultimate showcase of his curiosity, popping with shrubs and trees that people around town had never seen before: certain oaks, magnolias and maples.

The curiosity began with peach trees in Palisade. Taylor grew up there the son of a sharecropper who could barely read.

He grew up poor during the Great Depression, scrounging around the Grand Mesa for desirable bones to sell for something to eat.

“He had to be scrappy growing up,” Georgis said. “And he knew his way out of poverty was education.”

A high school teacher sparked the boy’s interest in Spanish and French, following earlier years in which he studied Native American languages on his own. He decided on linguistics as a profession.

A Fulbright scholarship took him to France in 1953. The Army took him to Germany a year later. The GI Bill took him to the University of California-Berkeley for a Ph.D. A girl he loved and the prospect of family later brought him back to Colorado.

Taylor retired in 1998 in Boulder. There he stayed with his shrubs and trees — except for the occasions when wanderlust inevitably tugged him back to the road.

At 88, he found himself collecting acorns far across Colorado’s southern border.

“He took a fall and shattered four ribs, punctured his lung and severed his spleen, and he got up and walked back to his car,” Georgis said. “He drove 200 miles back to Trinidad where he was staying in a Super 8 motel and called me.”

That was the end of collecting.

But nature’s wonder, that agave back at the greenhouse, captured Taylor’s imagination until the end.

The end is near for the plants. Clark, the greenhouse manager, expects the bloom to last through the end of this month.

His team has been harvesting seed to spread around the property, feeling inspired to continue the soaring, showy plant that has clearly inspired visitors.

“To look up and think how many decades went into that (flowering), it’s just amazing,” Clark said.

It’s been amazing to measure, he said. He’s noted as many as eight new inches every day.

Something Georgis heard about that rapid growth brought her back to the agave one recent afternoon, back to where a legacy lives.

“I want to put my hand on the stalk,” Georgis said. “I’ve heard if you put your hand on the stalk, you can actually feel it, the life force in it.”