WALNUT CREEK -- Confronted with the prickly facade of an "opuntia robusta" in the three-acre Ruth Bancroft Garden, most visitors do not think, "I want to eat that!"
The plant, falling into a classification generally referred to as "prickly pears, " is covered not only with obvious, dagger-like extrusions but with microscopic spiny needles called "glochids." Invisible to the eye but painful to the touch, they are Mother Nature's ingenious protective armor for the plant's deep red, beet-flavored fruit.
But on a sunny Saturday, armed with the expertise of docent Jody Morgan, two dozen brave and curious nibblers defied thorny peril and ate their way through an Exotic Fruit Tasting Tour at the Bancroft garden.
It was instantly obvious to see why the tour was a sellout -- lively visitors (many with a formidable supply of succulents knowledge) and an animated, expert tour guide.
Barry Rice and Beth Salvia traveled from Woodland, bringing their astrobiology professor/optical lab worker/portrait painter backgrounds and their "Any fruit tasting is fun!" attitudes.
"We came to see if there was something to incorporate into our front garden, " Salvia said. "We have fig trees and a vegetable garden, but we'd like to add water-wise plants that are edible."
John Valenzuela, an educator, horticulturist and chairman of the Golden Gate chapter of the California Rare Fruit Growers, was a walking encyclopedia but every bit the gentleman as he tossed in references to ancestral origins for various plants, or literary myths and legends to accompany Morgan's robust explanations.
The Bancroft garden was started by the now 104-year old Ruth Bancroft, who continues to live with, work among and add to the venerable collection. The garden could survive nearly an entire summer without watering, according to Morgan.
"We water once a week, but only to keep it looking best for visitors, " she explained.
Morgan, a Danville resident and a five-year garden docent, has a fascination with and tenderness for succulents, and a deep knowledge of the garden's -- and each plant's -- history.
"Invasive plants aren't dangerous, unless you let them grow unrestrained, " she said, in answer to a guest's question about an "undesirable" plant.
Morgan opened the gate to allow entry into Bancroft's private garden -- a special bonus of the tour as Bancroft's private property is not typically open to the public.
"I don't have a lot of nice things to say about this first plant ("Feijoa Sellowiana, " or "Pineapple Guava"), but Ruth is a collector and wanted variety, " Morgan said.
The offending plant's green, plum-sized fruits littered the ground; when cut, they yield a soft, kiwi-textured fruit.
"I liked the jelly palm better, " a visitor said, about the cherry-sized, orange balls tasted at the start of the tour.
In addition to scientific details about each plant's genetic code, soil conditioning, organic growing patterns (one plant fruits and flowers at the same time so that it is never "dormant") and "inorganic manipulations" (plants engineered to feed cattle), Morgan allowed visitors to discuss the flavor of each fruit.
"The difference, even within one species, is impressive, " said Lisa Damerel of Orinda. "But you can't just go up and pick it. It's spiky and spiny and you'll get stabbed."
Her companion and spouse Jordan, was caught by the wonder of finding himself surrounded by odd, edible plants and simply added, "Can you believe we're right in the middle of a city?"
Gathering at a table spread with try-it-again fruit platters, visitors clustered in small groups.
"Can you tell me more about the 370-year old Valley Oak that produces 2,000 pounds of acorn in one year?" a woman asked Morgan.
"Native people cleaned wounds and set mortar and substituted some of these plants for wood -- sustainable practice isn't new!" another visitor announced.
A 23-year-old hybrid agave, rising like a gigantic, 25-foot asparagus stalk, received a number of comments -- "amazing, " "impossible" and "imagine that for dinner!"
On a Bancroft garden tasting tour, that's the beautiful thing. There's no need to imagine -- just eat.