Arens and Ancient Garden in SF Chronicle – Hobart and William Smith Colleges \
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Arens and Ancient Garden in SF Chronicle

Associate Professor of Geoscience Nan Arens is quoted in a story in the San Francisco Chronicle about the Ancient Plant Garden at the San Francisco Botanical Garden, which she helped to renovate, drawing up the template designers then used.

“The redesign reflected a change in exhibit philosophy,” Arens is quoted as saying in the article.

“We wanted to give visitors a sense for what it would actually be like to visit those ancient ecosystems. We’re using plants as elements in an ecological palette rather than simply as interesting objects on display.”

The plants in the garden truly are species that existed in ancient times and have survived through to present.

“These plants were supremely adapted to their time and ecosystem. They dominated long ago – they are ancient,” explains Arens in the Chronicle.

Arens earned her B.S. and M.S. from The Pennsylvania State University and an M.A. and Ph.D. from Harvard University.

San Francisco Chronicle
Visitors time-travel at Ancient Plant Garden
Ron Sullivan, Joe Eaton • October 29, 2008

Names matter. That’s why the former Primitive Plant Garden at the San Francisco Botanical Garden is now the Ancient Plant Garden. Nan Arens, professor of geoscience at Hobart and William Smith Colleges in New York and adviser for the garden’s renovation, insisted: “Don’t call them primitive.”

Arens, currently in Australia, explained via e-mail: “For most people, ‘primitive’ has a connotation of being inferior, ready to be replaced by something better, more modern. We wanted people to understand that these plants were supremely adapted to their time and ecosystem. They dominated long ago – they are ancient.”

She might have added that they’re still here.

More than the name has changed. The garden, dedicated a couple of weeks ago, has been restructured as a stroll through deep time. You enter at the Devonian Period, when pond scum was the major form of plant life. A boardwalk leads through the Pennsylvanian, the period of fern-dominated coal swamps; the Jurassic, when palmlike cycads and early conifers flourished; and the Cretaceous, at the dawn of the flowering plants. By the time you reach the Eocene, plants have adapted to a drier, cooler world more like our own.

There are wonderful touches throughout. The pavement starting the path is impressed with tree-fern and ginkgo leaves. The footprints of a hadrosaur, a 3-ton Cretaceous plant-eating dinosaur, wander through the paving and off among the plants. A pebbled swale leads to a pool where water lilies, among the most ancient angiosperms, float.

Arens drew up the template, and designers Davis Dalbok and Tim O’Shea of Living Green brought it to life.

“We tried to create an ancient feeling,” O’Shea said. “We wanted people to think of the story line of plant evolution. The old garden was a bit of a jumble; we reorganized it with the narrative in mind.”

That required moving some tree ferns and magnolias around and removing plants that weren’t relevant to any of the garden’s time periods. They kept the gunneras, sometimes sold as “dinosaur chow,” whose pollen has been found in 93 million-year-old fossil deposits.

“The redesign reflected a change in exhibit philosophy,” Arens said. “We wanted to give visitors a sense for what it would actually be like to visit those ancient ecosystems. We’re using plants as elements in an ecological palette rather than simply as interesting objects on display.”

Dalbok and O’Shea worked pro bono on the project, funded by the Thomas Rohlen family. Mike Boss of Rock and Rose Building handled the rockwork, using recycled concrete from elsewhere in Golden Gate Park. San Francisco Recreation and Park Department workers built the decking.

Donations came from American Soil Products in Richmond and several nurseries, including Flora Grubb Gardens in San Francisco and Rancho Soledad Nursery in Rancho Santa Fe (San Diego County). The neighborly California Academy of Sciences provided the hadrosaur footprints, and the inimitable Carol Tang, its director of visitor interpretive programs, was involved in the planning process.

The designers take special pride in the garden’s cycads, the stars of the Jurassic collection. “We’re really fortunate to have had great donors present these very valuable cycads,” Dalbok said. “This could be the most important cycad collection in the Bay Area, for specimen quality and the breadth of the collection,” O’Shea added. Specimens have been provided with computer chips, like pets, for security.

Cycads are what make the Jurassic Dalbok’s favorite period. As a teenager in Santa Barbara, he used to surreptitiously visit Lotusland when Ganna Walska was amassing her legendary cycad collection. “It was one of her last endeavors,” he recalled. “She would send collectors to South Africa, which you can’t do anymore. Lotusland is where I became inspired in so many ways.”

Their neighbors in the Jurassic section include podocarps and other ancient conifers, some from the botanical wonderland of New Caledonia in the South Pacific. There are also ginkgos, conifer relatives that went extinct in the wild but were preserved in Chinese temple gardens.

Some Jurassic cycads may have been pollinated by insects, but that world-changing partnership really took off in the Cretaceous, represented in the garden by magnolias, star-anise trees, water lilies and pipevines. Arens wanted to include an amborella, the closest living relative of the first flowering plants, but none was available; this New Caledonian native might be too delicate to withstand a San Francisco winter anyway.

Arens said that while many plant species died out at the end of the Cretaceous along with the dinosaurs, representatives of most families survived.

“Although there were species extinctions, there wasn’t a revolution in vegetation,” she said. Plant life didn’t change dramatically until the Eocene, after wild swings in global climate settled into a cooling trend.
“The bones of the Ancient Plant Garden are all there,” Dalbok said. Future enhancements may include replicas of ancient animals lurking among the ferns, and maybe even a Jurassic soundtrack.

Note: Last week’s Dirt inexcusably omitted the Web address for the Mill Valley Children’s Garden. It’s

The Lincoln School garden in Richmond doesn’t have a Web site, but the school does:

— San Francisco Botanical Garden at Strybing Arboretum, Ninth Avenue at Lincoln Way, Golden Gate Park, San Francisco. Open 8 a.m.-4:30 p.m. weekdays, 10 a.m.-5 p.m. weekends and holidays.
— “The Emerald Planet: How Plants Changed Earth’s History,” by David Beerling (Oxford University Press, 304 pages, $18.95 paperback).
— Living Green Plantscape Design, 150 15th St., San Francisco. (415) 864-2251,
— Rock & Rose Landscapes, 1615 Cortland Ave., San Francisco. (415) 824-3458,
Joe Eaton and Ron Sullivan are naturalists and freelance garden writers in Berkeley. Check out their Web site at or e-mail them at