A walk in the woods with Ernie Schuyler is like no other.

He ambles along in slo-mo, stopping here, poking there, looking up, down, overhead and sideways, exclaiming "Wow!" and "Look at this!" and, with humble candor, "How did I miss that?"

Schuyler, curator emeritus of botany at the Academy of Natural Sciences, prefers "Ernie" to his given name, Alfred. He's a beer connoisseur in a baseball cap who, despite his fancy title and expertise on sedges and mid-Atlantic plants, is about as down-to-earth as a learned botanist can be.

Which is where you'll find him these days: down to earth, literally, walking the grounds at Ker-Feal, the 138-acre retreat in Chester Springs that belonged to the late Albert and Laura Barnes.

At the behest of the Barnes Foundation, Schuyler is doing a plant inventory at this once showy estate, which has lain fallow since Albert Barnes' death on July 24, 1951.

(Barnes was driving country roads back to the foundation in Merion from Ker-Feal when he ran a stop sign and was hit, killed almost instantly by a tractor-trailer. Laura Barnes continued to use the house until she died in 1966, but is said to have never again spent the night there after her husband's death.)

Four overgrown terraces barely hint of their magazine-quality gardens back in the day. Once-smooth lawns are tufted with dandelions. And the surrounding forest is so choked with invasive plants that much of the native flora is being squeezed out.

A caretaker lives atop the garage, in view of the 1775 fieldstone farmhouse, which is shuttered tight. The house still holds Albert Barnes' collection of more than 2,000 pieces of early American decorative art and furniture, a fascination he once suggested derived from his Pennsylvania Dutch grandmother.

Schuyler is more at home outside at Ker-Feal than inside. His job is to sort out what's growing in the meadows, ponds and streambeds, in the old flower beds and forests.

Eventually, says Jacob Thomas, director of the Barnes' arboretum in Merion, it's hoped that Ker-Feal can become what Barnes stated in his will: "a living museum of art and . . . a botanical garden to be used as part of the educational purposes of the Barnes Foundation in both the art and horticulture programs."

Someday, perhaps.

"For now, the priority is the new facility downtown," Thomas says. "For the foreseeable future, Ker-Feal will stay as it is."

The foundation's $6 billion art collection is scheduled to move from Latchs Lane in Merion to the Benjamin Franklin Parkway; its art school and 12-acre arboretum will stay put. Despite the country estate's nebulous future, in 2006 the foundation asked Schuyler to take a botanical look around Ker-Feal, which is Breton for "House of Fidèle," after Barnes' favorite pooch.

(He adopted Fidèle in Brittany, during an art-buying trip to France.)

Imagine Albert on the porch, Fidèle at his feet, chatting with British actor Charles Laughton or philosopher John Dewey. Both were such frequent guests at Ker-Feal, they had their own bedrooms.

Imagine Laura's summer terraces ablaze with roses, the botanical garden she fashioned from a quartz quarry and her unusual hand-picked trees and shrubs. She also had an orchard, a bamboo grove, a heath garden and a blueberry patch, of which little survives.

Today, in a place that once hosted classes in horticulture, botany and plant geography, Schuyler has cataloged 400 plant species and identified about 80 percent of them. Each specimen is preserved in a giant flower press.

Sounds pretty arcane, except this botanist finds fun in the forest, too. "I have a pressing engagement," he says impishly, shutting the flower press.

Schuyler's botanical bent may have been foreshadowed. When Schuyler was growing up in western New York, his father's farm supplied a half-million trees for a government erosion-control program. Schuyler and his brother helped plant them.

"My brother was more interested in girls, but I loved it," Schuyler recalls, inching along a narrow path in Ker-Feal's humid woods. (The estate is closed to the public, but this path - part of the Horse Shoe Trail that runs from Valley Forge to Harrisburg - is accessible.)

Then he turns serious.

His work documenting that "this plant grew in this place at this time" will create a historical record to monitor environmental changes in the future. The project also is about "managing a landscape and getting people to appreciate not only nature but rural living and farming."

"To me, this is poetic," Schuyler continues, his footsteps crackling on the forest floor. "I'm turned on, particularly when I see a rare plant or one that's new to me or I'm curious about."

This part of the forest was probably cut down years ago, so he finds that many nonnative plants, opportunists all, have moved in. One - autumn olive, an Asian native introduced in this country as a highway barrier in the 1960s - has seized the day at Ker-Feal.

So has Japanese multiflora rose, which was encouraged by the U.S. Soil Conservation Service in the 1930s as a living fence. "Dastardly," Schuyler calls it, while pointing out other invaders with human sponsors: vinca, burning bush, privet, Oriental bittersweet and Japanese barberry.

Another part of the forest, one that likely was never cleared, has many more, well-behaved natives. Schuyler delightedly offers correct Latin nomenclature for plants with mellifluous common names, such as black snakeroot and jack-in-the-pulpit, sweet cicely, rue anemone, blackhaw and maple-leaved viburnum.

Here, in this geologically complex area, he sees a healthy mix of plants. "And that's good. We want a diverse flora," says Schuyler, who hopes to finish his inventory next month

Three hours after it began, his walk in the woods is finished at last.

"When you walk through the woods with a botanist, it's very, very slow," Schuyler notes with a chuckle, before setting off for another pressing engagement.

Virginia A. Smith blogs about gardening at http://go.philly.com/kisstheearth.EndText

Contact gardening writer Virginia Smith at 215-854-5720 or vsmith@phillynews.com.