The spellbinding saga of a humble weed

Seed to Seed: The Secret Life of Plants
By Nicholas Harberd
Bloomsbury, 320 pp., illustrated, $24.95

Flowers: How They Changed the World
By William C. Burger
Prometheus, 337 pp., illustrated, $23

Science and art are disparate fields, right? In the newspaper, they live in separate sections. On a college campus, biology labs are held in the science building. Drawing classes are held in the fine arts building, a half-mile away.

And why shouldn't they be? Art is subjective and science is objective, right? Artists are urged to work with passion and ardor. Scientists are urged to work with detachment, aloofness. Put on the white coat, leave your emotions in the locker.

Right?

Wrong. I believe these divisions are arbitrary. The perception that science and art are mutually exclusive fields is mostly useless. Fundamentally, artists and scientists are concerned with an identical proposition: trying to describe the world as they see it. Both attempt to understand what it means to be human.

One point to consider: the day-to-day lives of artists and scientists aren't all that different. Eat breakfast, go to work, break the ice that has formed overnight, and start confronting problems. Whether you're writing a novel, making a diagnosis, painting a mural, or examining volcanic rocks, you're working through a series of problems of varying complexity. Like artists, scientists get entranced, have revelations, bog down in the mundanity of repetitive tasks. Like artists, scientists start with an idea and test it, over time, until they believe it is ready to be communicated to others. And, like artists, scientists occasionally get blocked. Research stalls, a barrier impedes progress, and the idea that set you on fire yesterday seems cold and uninspiring today.

Because a wonderful film or groundbreaking theorem tends to conceal the difficulties of its creation behind the elegance of the final product, diaries often offer the clearest windows into an artist's, or scientist's, day-to-day struggles: the initial excitement, the false starts, the swings between elation and frustration.

This month sees the publication of a perfect example: ''Seed to Seed: The Secret Life of Plants," by Nicholas Harberd.

Harberd is an eminent plant geneticist in the United Kingdom. Two years ago, he started to feel his team's course of research had played itself out. He'd spent, he says, ''too long amongst computers, microscopes, and test tubes." He was, for all intents and purposes, blocked.

''If I can work out what the next question is," he writes, ''the path will become clearer." Over the course of 12 months, ''Seed to Seed" charts his day-to-day search for that question.

Where does he find it?

In a thale-cress plant. Thale-cress is a velvety, foot-high weed in the mustard family. Like the mouse or fruit fly, it is humble, common, inconspicuous, and a darling of lab scientists.

Harberd had studied thale-cress plants for over a decade. But he'd never bothered to examine even a single specimen growing in the wild. Until now.

A short bike ride from his home, Harberd finds a 4-inch-wide thale-cress growing on top of a grave. He visits it, and its descendants, several times a month for a year. From that little plant, and from Harberd's devoted attention to it, blooms a remarkable book.

''I've been spending my life shaping a vision of hidden molecular events, invisible things that drive life," he writes. His book is notable because he is as comfortable explaining the underpinnings of cell growth as marveling at the tiny, self-contained miracle that is a seed.

You learn, you struggle in tandem with plant and author, you get to a point -- seriously --where watching a hungry slug creep toward the little thale-cress, or discovering that most of it has been devoured overnight by something (rabbit?), floods you with empathy. And, along with Harberd, you find yourself overflowing with wonder at the outrageously complex and resilient organism that is a weed.

Another lovely book about plants is new this month: William C. Burger's ''Flowers: How They Changed the World." This is a carefully written survey of how flowering plants, over millions of years, have determined the world we live in.

''Without the flowering plants," Burger argues, ''primates would not have diversified, long-armed apes would not have swung through the canopies of tropical forests, and herbivore-rich grasslands would not have come into existence."

Both Harberd and Burger excel at demonstrating how evolution has continued to refine the astonishingly complicated architecture of plants, so that you close their books and go out into the springtime and see a richer, more beautiful world.

Right now a vast and highly orchestrated network of information is operating in every plant in your front yard, messages radiating between cells along threads of cytoplasm; the plants are fending off pests and pathogens, perhaps even emitting chemical signals to warn neighbors. Slender rootlets are prowling the soil, sucking up water and nutrients; photoreceptors are monitoring the amount of daylight; water is coursing up through xylem; sugars and nutrients are dribbling down through phloem. Leaves are tossing about, absorbing carbon dioxide, releasing water and oxygen -- the whirling ballet of photosynthesis is taking place just beyond your windows, transforming the energy of the sun into the molecules that feed all plants, all animals, and even you.

Artist or scientist, it's enough to take your breath away.

Anthony Doerr is the author of ''The Shell Collector" and ''About Grace."