One of the projects they’re currently pursuing concerns a monster. Most people think that the blue whale is the largest organism on earth, but it’s actually a fungus. A vast pathogenic fungus that takes up 2,384 acres in the Pacific Northwest and is estimated to be over eight thousand years old.

On the surface, the yellow-capped honey mushrooms pop up, but beneath the soil, the rhizomorphs slowly finger their way outward, filaments that weave tighter and tighter together, eventually forming a kind of mat. The digestive enzymes that it secretes kill conifers. Individual units are known as hyphae, but the larger network is called the mycelium. These are identical cells that communicate and coordinate for a common purpose. Botanists have tried to find its edge but given up. One of the goals of Jack’s lab is to map it completely, expose its limit.

He knows that studying fungus isn’t exactly cool, but giant mushrooms excite even the most scientifically disinclined.

The building is cold with air-conditioning, brightly lit with fluorescence, and still smells like fresh paint. He follows a branching series of hallways, his shoes damp and squeaking, until he arrives at the lab. He is the principal investigator, so his name is on the door. The sight of it fills him with a mix of pride and guilt. He key-cards his way in with a bleep. Inside he finds Darla, one of his grad students.

“Hey,” he says. He flops off his shoulder bag and collapses onto a chair in front of a computer. “What’s the latest from the field?”

He’s so distracted that it takes him a moment to realize she isn’t responding.

“Darla?”

She’s in her late twenties, a Berkeley grad. She keeps her hair short and wears long, dangly earrings made of fruit or feathers. He guesses she recently came back from a survey, because she’s wearing boots and jeans with mud still speckling them, and dirty sample vials are spread out across the table. She is tall and lanky, so the bow in her back appears especially dramatic, a spinal parabola. From her posture, he initially assumed she was hunched over a microscope, but now he hears her breathing fiercely—in through her nose, out through her mouth—and recognizes that she is doubled over in pain.

“Everything okay?” he says and gets up to approach her. “Darla? Anything I can do?”

He can see now that her eyes are scrunched shut and her hands balled into fists. He thinks about touching her back, but his hand hesitates in the air a few inches from her. He can hear now the static pop and gargle of her breathing, a pneumoniac thickness.

“I don’t,” she says. “Feel so.”