"I didn't know this before, but plants have sex," says Kevin Delin. He's gesturing toward two huge cycads, palmlike fugitives from the Dinosaur Age growing in a corner of the Huntington Botanical Gardens, a sanctuary for 15,000 rare plant species in San Marino, CA. Delin's ignorance of botany is excusable. He's an engineer from NASA's nearby Jet Propulsion Laboratory, and what truly interest him are not the male and female cycads but the pair of "sensor web pods" lodged in the ground under the plants. Each pod is the size of a handheld computer and contains a processor, battery, solar cell, radio, memory, and sensors to monitor heat, humidity, and soil moisture. The pods are the surrogate eyes, ears, and even brains of the garden's curators, keeping track of how much sunlight and rain the plants are getting-critical factors for cycads, which need specific conditions to reproduce.

Sensors are nothing new. A car, for instance, uses dozens of them to monitor factors such as engine conditions. But the sensors in today's automobiles, factories, and office buildings are, for the most part, dumb. They lack the intelligence to analyze or act on their findings; instead, they send measurements back to a central processor. Most current sensors are also stuck in place, with any move requiring expensive rewiring. Delin's pods are different. They talk wirelessly with each other and with 18 other pods in the garden, forming their own intelligent network. Every few minutes, the pods update each other about their latest readings, together process the information into an overall picture of temperature and soil conditions, and send this analysis to the curators. It's as if an autonomous, highly aware computer were spread across 40 hectares of landscape.