Rust



Our move brought me over a lift-bridge in the middle of a rainy night. Tracy had taken the place and set up housekeeping, and now she was showing me the way home. Our sons were in the back, one talking, the other sleeping. The road curved into the moist dark. “I’ll bet you’re wondering what I got you into,” Tracy said.

But in the morning the place was sunshine and the chatter of finches. We were to live in a village in the upper Midwest. The front of our place was a busy and badly paved road; the back was a straggling wood. Winter nights, you’d be able to see all the way through the naked forest to the houses on the other side. But for now it was spring and I had the illusion of a wilderness.

The Eastern red cedar tree in our back yard looked bad—shaggy, wasted, a dandruff of gray decline mixed in with the healthier bluish-green needles. We had seen the cause already, in the form of little spiky galls hanging here and there like drab Christmas ornaments. Each of these ornaments was smaller than a golf ball and seemingly made of wood, which might make you think it was some healthy part of the tree. I picked one off. Each little spike was a spout: a hole surrounded by a sharp woody projection. The ball resisted pressure only as much as a fruit might. Carrying it to the cement walk, I crushed it under my heel. It wasn't difficult. Inside, the thing was pulpy and fibrous, its strands of vegetable matter radiating from a tight core. Its wet texture was like that of the new wood you can find under a tree's bark.

I knew this from my trip to bat country as cedar apple rust, a parasite with a provocative life cycle. On the leaves and fruit of apple trees, this fungus manifests itself as leathery patches of discoloration. On red cedar trees, it takes the form of these woody galls. The apple and cedar forms of this parasite are different stages of a single life cycle which involves both sexual and asexual spores.

To look at it, though, I wouldn't have recognized this sphere as alien to the tree, made as it was of the tree's own tissues. The tree itself makes the sphere, acting on instructions from the fungus, like a human body producing a tumorous mass at the command of rogue cells. My sons gathered a few and smashed them with a tenderizing mallet to examine their insides.

Rain revealed more. It rained for two or three days, a steady soak that had my sons whooping barefoot on the lawn. One day they were all excitement: "The parasite opened up!"


Indeed. All over the fifty-foot tree, the galls had effloresced. Through each spiky spout, a vivid orange tentacle projected. It seemed as if the tree had collided with a swarm of sea anemones.

I bent a bough down so the boys could see. My older son poked at one gall
and proclaimed it slimy. I tried its texture myself: wet gummy worms. Our gentlest touches marred them. I almost expected them to recoil.

*

It used to be said that a fungus was a sort of defective or degenerate plant, one that lacked chlorophyll and so could not make its own food. It was thus reduced to feeding off the work of others—grubbing in the soil to devour dead animals, fallen leaves, and damp wood.

Biologists know better now, partly because of advances in genetics. In the last few years, DNA sequencing has revealed strong evidence for all sorts of things we hardly could have suspected—that whales belong among the even-toed hoofed mammals, that dinosaurs and birds are more closely related to crocodiles than turtles are. The method behind this is to look for similar strings of DNA, then analyze them statistically. All life on earth comes from a common stock; the more dissimilar two life forms are genetically, the longer it's been since they diverged. By applying sophisticated mathematical models, geneticists can estimate how long it takes for certain kinds of differences to arise. By comparing these numbers, they can deduce how closely related different kinds of living things are.

But this re-evaluation of relationships goes deeper than the shifting of animals among orders. Our vision of life at the most basic levels has altered too; the kingdoms, the very fundaments of Linnaean biology, have had to be shifted about. The fungi comprise their own kingdom now. We understand, better than we did at least, what they are. Certain organisms we had called fungi because they were slimy and repulsive and because we didn't know where else to put them—the slime molds, for example—have been exiled from the kingdom. That is not too hard to take, because few of us encounter slime molds with any regularity.

What's harder to take is that fungi turn out to be our kinsmen. They are not plants at all; they are closest to the animals—to us.

*

We usually think of fungus as an unhealthy thing, a sign of disease. That's a slander, for parasitism is only one of the possibilities of fungi.

In the woods behind my house I find uncountable lichens. These are, as every high school student learns, symbiotes, a fungus paired with an alga or a similar life form. They are the surface I touch when I lay my hand on a fallen tree; they are the first flaky layer my handsaw bites through when I gather dead wood. When my sons climb to prospect for higher views, half their footholds are ledges of lichen or simple fungus.

I called them uncountable. This is only partly because they are numerous. The other reason I can't quantify them is that they lack integrity. The whole leeward side of a certain box elder tree is crusted with green: where does one lichen end and another begin?

Fungi are often colonial, rather than singular. A million fungal filaments in a patch of soil may be in communication of a sort, all of them sending strands toward a food source when one detects it. There is, of course, no brain, no central command, merely a shared purpose. If we consider one such aggregation a single individual, then the largest life forms we know are fungal: stretching for miles within the soil, their mass rivaling that of the blue whales or perhaps even the redwoods.

If the individuality we tend to think of as fundamental is lacking in the fungi, then so are the species boundaries. Lichens are only one kind of symbiosis; the fungi have many. One style, for example, is the mycorrhiza, a combination of fungi with the roots of a plant. The fungi reach where the plant cannot, bringing in minerals the plant needs; the plant shares the food it makes from light and water. Though most people are perhaps not familiar with this arrangement, it is the basis of life as we know it. At least 80% of plants cohabit in such a manner—some estimates go as high as 90. The boundaries are not exactly where we are accustomed to draw them, because, practically speaking, the average tree or weed or grass is not merely a plant, but a combination of plant and fungus.

It is not easy to grasp this, or to see it without benefit of excavation, dissection, and microscopy. But the signs are visible, if you look. Sometimes in wet weather I find an arc of mushrooms in my front yard. It is this arcing distribution that reveals hidden relationships, for the focus of the arc is a maple tree. The mushrooms are the genitals of fungi intimate with the tree. It is possible to trace its thicker roots, barely concealed in the dirt, to aggregations of mushrooms.

*

A moody morning after rain. The rusts had poured forth their tentacles again, but after a few hours the tentacles had withered to brown scraps. My oldest son and I decided to retrieve one of them for study. He held a slender branch taut while I cut. The shears met in the wet wood with a squeak and a snap; the branch sprang upward, leaving its severed extremity in my son's hands. He plucked the rust off it avidly.

We watered it in a jar and it revived. Overnight, new tendrils of orange slime pushed their way out through the colandered sphere. It did not need rain, then; any drenching would do.

The next stage of our inquiry was a white plastic cup. We had learned that the rust spreads orange spores while it's active. Looking over its gelatinous tentacles, I had no doubt our specimen was alive, but we made the experiment anyway. Into the little white cup it went with a fresh supply of water. In the morning, the water showed orange against the cup—its spores coloring the water like a weak dose of Tang.

For a few days, my sons were always bringing in bigger, juicier specimens of the rust, poking them with sticks, marveling at them. Then their interest dwindled, and I'd find week-old jars of the things on shelves and window sills, the tentacles half dissolved in the water, retaining only their color.

*

I always suspected we were cousins. The fungi don't move the way we do, but some of them, the most visible ones, grow so fast it seems a sign of animal life: the mushroom big as a human fist found on your lawn the day after a rain, for example. I have a vivid childhood memory: something smooth and white nesting in the grass, the size and shape of a chicken egg, hardboiled and peeled. It was not an egg, however: my dog evinced no interest in it. Something about it made me reticent to touch it. It had no smell, but something about it reminded me of dog feces, or perhaps merely the Platonic form of disgust. The weird notion that it was an eyeball crossed my mind, and I went so far as to turn it over with a twig, looking for an iris. It was this operation that revealed its true nature to me, for it tore open under the stick and revealed, first, the stringy origami I associated with the insides of some mushrooms. The other thing this tearing revealed was the smell, which had hitherto been undetectable, the smell of rotten flesh.

Or maybe their overnight appearances simply seem like a sinister kind of magic. Toadstools, elves.

*

It is not only the plants that live in symbiosis with fungi. We animals do it, too. We do not like to think of it, because we have for so long conceived of microbes as unclean things, as invaders. But of course we have always been symbionts, dependent on the microbes in our guts to digest our food. We have colonies of fungus inside us as well. A so-called yeast infection is really an imbalance. It is not a problem that the yeasts are in the human body—they always are. It's a problem that their numbers have, because of some teetering of the pH level, exceeded their usual bounds. It is a natural thing to share our bodies with them, and with all manner of other organisms. As a tree is not simply a tree, we are not simply what we think we are.

Which is not to exonerate them all. Plenty of fungi are pure parasites, and these have invaded almost every kind of life. There are specialized fungal parasites of single-celled diatoms and even of other fungi. And some of these cause serious harm. The rust on my cedar tree was bad for it; it must have been even worse for the apple trees in the neighborhood, for the leaves of the apple are slowly pierced through by the rust, until spore-shooting orange masts sprout from their undersides. The fruit of the apple, too, may be ruined, its hide marred by soft brown patches.

So, too, with the human form. There are fungi to make the feet and the testicles itch, fungi to discolor and deform the fingernails. And there are neighborly fungi content to live within us unobserved, but which will blossom, in the case of a ruined immune system, into devouring sores, inside and out. It is a common enough way for people with AIDS to die.

*

Two years have passed since the last time our cedar was dazzling in its orange jewelry. The next year we waited in vain for another blooming of that odd fungal life. We had trimmed them off where we could reach, hoping to save the tree, but it wasn't our earthbound efforts that drove them away. We could still see dozens of them higher up, dry and drab, refusing to bloom. This is the way of the rust. It persists on apple trees, but on a cedar it gives its life to the wind and leaves its old self to rot.

Our tree grows shaggier year by year, more patched with vanilla and auburn. Within the greenery that remains I can reach dozens of lifeless branches. A good yank is sure to be rewarded with the crack of dead wood, dry enough to burn. The whole tree is ugly now, truth to tell. It reminds me of nothing so much as the shaggy head of a neglected old man.

Not that I neglect it. I prune; I am doing what I can to save its life. But it is dying, I'm sure of it. When we walk beneath it, mosquitoes and blackflies come for us by the swarm.


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