Agnes liked to examine her body as a measurable quantity. Though our extra room was always intended as her office, she never used it much before, preferring to stay late in the lab, with the precision of the instruments, the climate controls, the rooms full of green things. Sometimes I would meet her there, and if it was empty she would take me into her glassed-in worlds, small farms and rain forests and flower gardens grown between windows. Once it was warmer outside, I thought I’d like to build her a greenhouse. Now, her office was filled up with samples, with sketches and notes and slivers of mushroom on microscope slides. On spare pages of her sketchbook, she drew rabbits with clubby mushroom paws, deer with antlers of branching fungi.

I brought her strands of her hair I’d picked off the floor, a pillowcase she’d drooled on, a nail clipping, collecting pieces of her from all around the house and returning them. She would look at them through the lens of her microscope, hum through her teeth, take photographs. I liked how closely she looked at herself now. It was a beautiful way to live.

In her absence, I cleaned the fridge and swept the floors. I put the rent check in my wallet, so I would not forget to bring it to the post office. Now, Agnes wrote articles for glossy periodicals, Nature, National Geographic, Scientific American, which appeared regularly in our PO box, with Agnes’s words printed finely beneath someone else’s pictures of a breaching dolphin or a foreign sky. I picked up jobs at construction sites, as a dishwasher, moving furniture, though I preferred more and more to stay home, when I could. I did not like to leave Agnes alone.

I washed the day’s dishes in the hot sink, sponged the building grime off the counters. I liked to end my day with some amount of cleaning. Outside, the afternoon was sliding toward the night, the sky a purplish flush. I turned the lights on, so that when Agnes came back the cottage would be glowing for her. I took the mushrooms outside to bury before it got too cold.

Our garden is bordered by an unsteady white fence, beyond which the woods are a tender green in the evening light, veined with deer paths. The fence is a porous boundary. Agnes’s strawberry plants push through to the other side, and when we dig along it we find roots that aren’t ours.

I dug deep and close to the house. Though Agnes said it was silly, I feared the deer and the squirrels turning things up. They wouldn’t eat the mushrooms, Agnes said. She said, “Animals know what things are poison. How else would they live?” I preferred caution anyway. I dug the hole deep and narrow, and into it I poured all the poisonous ones. Agnes’s death caps, her false morels, the destroying angels.