Hardly articulate, the tiny strangleweed, a pale parasitic plant, can sense the presence of friends, foes, and food, and make adroit decisions on how to approach them.
Mustard weed, a common plant with a six-week life cycle, can't find its way in the world if its root-tip statolith - a starchy "brain" that communicates with the rest of the plant - is cut off.
The ground-hugging mayapple plans its growth two years into the future, based on computations of weather patterns. And many who visit the redwoods of the Northwest come away awed by the trees' survival for millenniums - a journey that, for some trees, precedes the Parthenon.
As trowel-wielding scientists dig up a trove of new findings, even those skeptical of the evolving paradigm of "plant intelligence" acknowledge that, down to the simplest magnolia or fern, flora have the smarts of the forest. Some scientists say they carefully consider their environment, speculate on the future, conquer territory and enemies, and are often capable of forethought - revelations that could affect everyone from gardeners to philosophers.
Indeed, extraordinary new findings on how plants investigate and respond to their environments are part of a sprouting debate over the nature of intelligence itself.
"The attitude of people is changing quite substantially," says Anthony Trewavas, a plant
biochemist at the University of Edinburgh in Scotland and a prominent scholar of plant intelligence. "The idea of intelligence is going from the very narrow view that it's just human to something that's much more generally found in life."
To be sure, there are no signs of Socratic logic or Shakespearean thought, and the subject of plant "brains" has sparked heated exchanges at botany conferences. Plants, skeptics scoff, surely don't fall in love, bake soufflés, or ponder poetry. And can a simple reaction to one's environment truly qualify as active, intentional reasoning?