At the top of a small hill in suburban southern California, there is what appears to be a thicket of stunted, gnarled oak trees wedged between a pile of boulders. A passerby would likely miss this ancient, biological wonder.
The entire grove of trunks is in fact one plant, a newly discovered Palmer's oak (Quercus palmeri) that researchers estimate is over 13,000 years old, making it one of the oldest plants on Earth.
Researchers, led by Jeffery Ross-Ibarra of the University of California, Davis, found the tree a decade ago during a routine survey of local plant life.
It's easy to miss; none of its 70 stems get more than a few feet tall, and it grows in a boulder pile that doubles as shelter from the area's buffeting winds.
At first glance, the scientists thought it was an isolated grove of trees, but something didn't add up: None of them produced fertile acorns, so the plants couldn't reproduce.
The trees were a little too similar in appearance, too -- almost like identical twins. And Palmer's oaks typically don't grow in the hot, parched environs of Riverside County.