Alan Zale for The New York Times

In midsummer, the prized black trumpet sounded its horn from the forest floor in the Bronx. The coral-pink Merulius, never before seen east of Ohio, turned up in a park in Queens.

Then came the near-hurricane, and clusters of aptly named Phallus rubicundus, the giant stinkhorn, rudely reared their slimy heads from piles of wood mulch in Prospect Park. In Harlem, gray-brown umbrellas sprouted stalactite-like from a couple’s apartment ceiling.

Now, in the drenched autumn of what is already the fourth wettest year ever recorded in New York City, the creamy-white giant puffballs have reached the size of human skulls. And in Central Park, beside the lawns carpeted with amber honey mushroom, dense frills of delectable hen-of-the-woods explode from oak trunks by the bushelful, tempting those who would bend the city ban on foraging in parks (it mentions only “vegetation,” and mushrooms, after all, are not plants) and mocking the foodies who pay $35 a pound and up at the gourmet grocer nearby.

In and around the city, seemingly from every nook, cranny and sidewalk crack, in cemeteries and street-tree pits and median strips, months of biblical rains have yielded a prodigious harvest of mushrooms in a riot of rainbow colors and in every possible shape, size, texture and degree of edibility – savory, poisonous, even psychotropic.

Mycophiles have spent the season in a sort of extended delirium.

Alan Zale for The New York Times

“It’s that kind of year that people will talk about in the future: ‘Remember 2011, the year the hen took over New York?’ ” said Gary Lincoff, author of “The Complete Mushroom Hunter” and an instructor of a mushroom-identification class at the New York Botanical Garden. “Two years ago, I found one hen-of-the-woods in Central Park. This year I’m finding two or three clumps per tree.”

New Yorkers who seldom pay attention to nature have taken note, too. “A group of grotesque white mushrooms growing in a planter on 88th Street between Riverside Drive and West End Avenue are attracting large crowds,” the blog West Side Rag reported last month in a piece that read like a “War of the Worlds” dispatch.

In some quarters, the mushroom visitors have been less than welcome. After the August earthquake cracked open the roof of his building in Kensington, Brooklyn, and Tropical Storm Irene brought gallons of rain into his top-floor apartment, Ryan Meisheid, 29, found off-white mini-toadstools sprouting from the ceiling. He got out the bleach. “Mushrooms inside my apartment where they should not be growing equals bad,” he said.

In Harlem, in an apartment plagued with leaks, Nicole Press, a stage manager, was getting a massage from her husband one night when something in the corner up above caught her eye.

Nicole Press

“In the shadows of the candle I just saw this dark thing,” she said. Four cone-headed mushrooms protruded where wall met ceiling; they had not been there in the morning. Mr. Lincoff identified them, from a photograph Ms. Press had sent in, as inky caps. They make a great soup stock, he said. Alternatively, he said, “if you put it on a plate, it’ll disintegrate and turn into a muck, and you can use it to paint a picture.”

Even in a normal year, Mr. Lincoff said, “The city is a phenomenal place to go mushrooming.” A continuing survey by the New York Mycological Society has turned up over 500 different mushrooms in the city, more than 200 in Central Park alone.

The key is New York’s mix of wild and cultivated nature. “The city has 20 different oak species, some introduced, some native, and they all support different kinds of mushrooms,” he said.

Mushroom spores, Mr. Lincoff said, are all around us, floating on the air. All they need is moisture and a little bit of food to set down rootlike mycelia and send up fruiting bodies, as the above-ground portions of the mushroom are known. Lots of things can qualify as food. Last year, Mr. Lincoff said, he got a call when oyster mushrooms shot up between the floor tiles of a radiation center at a Brooklyn hospital. “They somehow imagined mushrooms and radiation go together and thought maybe the mushrooms were indicating a radiation leak,” he recalled. The mushrooms had simply been eating the glue that held the tiles.

While some edible mushrooms are so distinctive that even a novice can pick them without fear — giant puffballs, or chicken-of-the-woods, a yellow-orange explosion that appears on logs (and does, indeed, taste like chicken) — mycologists recommend that amateurs not eat questionable specimens without confirming their identity using a guidebook and spore prints. This includes the varyingly hallucinogenic species known to grow in the New York area, most of which are legal to possess.

At the mycological society’s weekly show-and-tell at a community center in TriBeCa on Monday, members nibbled on gin-marinated nuggets of a nutty fungus known as aborted pinkgill and gathered at a table laid with specimens resembling, among other things, clumps of orange hair, purulent pink-red pimples, delicate petrified bone, giant rusty amoeba crawling across a branch, and tiny bird’s nests complete with tinier eggs.

Alan Zale for The New York Times

Mr. Lincoff bestowed “best in show” honors on a crabmeat-like bearded hedgehog, occasionally spotted in very expensive restaurants. One member, Ethan Crenson, waved around a rotting oyster mushroom the size of a hand fan he had found in Prospect Park that afternoon. “There were four or five others like it,” he said.

Two days before, Mr. Lincoff had been one of the leaders of the mycological society’s annual hunt in Woodlawn Cemetery in the Bronx, a majestic 400-acre haven of dignified decay. On a crisp morning, two dozen seekers fanned out like grownups at an Easter egg hunt, lifting low-hanging branches and peering around the corners of mausoleums.

Beneath a juniper tree, Mr. Lincoff found a small knife. “Here’s a good sign,” he said. “That’s not the sign of a murderer. That’s a sign of a mushroom hunter who left his knife here.”

A professor from New Zealand brought over a handful of firm-fleshed tawny mushrooms, their undersides tinged corpsy blue. “You’ve found the jackpot,” Mr. Lincoff said: the fall’s first specimens of blewit, a choice edible “more like an entree than a side dish.”

Afterwards, on a picnic table near the cemetery entrance, Athena Kokoronis, a choreographer who has worked with Mr. Lincoff on a ballet about mushrooms, set down a paper shopping bag bulging with hen-of-the-woods. She explained her foraging technique.

“Every time I saw a large tree, I danced around the entire tree, and then went on to the next one.”

She stepped away to demonstrate and – “Oh! I think I just stepped on a mushroom.”