King trumpets that have a texture almost as firm and meaty as young porcini; shimeji that have a flavor that is wonderfully nutty; hen of the woods, with a taste as earthy as their name. If you still think the cutting edge in grocery store mushrooms is enoki, shiitake and portobello, you've got some very pleasant surprises coming.

And if one partnership has its way, there are going to be plenty of those surprises available.

The Japanese mushroom giant Hokto Corp. is working with its American partner, Golden Gourmet Mushrooms, to build a massive, modern growing facility in Southern California that within a couple years will be producing as many as 6 million pounds of exotic mushrooms annually.

That's more than triple the amount of king trumpets, shimeji and hen of the woods sold in the United States last year. And although, according to the U.S. Department of Agriculture, they represent less than 1 percent of all fresh mushroom sales, they're part of a segment that is increasingly profitable.

While sales of the common button-type mushrooms have been mostly flat for the past five years, specialty mushroom sales increased 9 percent last year in spite of an average cost that's more than double the cost of buttons. "In the big picture, we're a fly on an elephant's behind," says Golden Gourmet President and Chief Executive Craig Anderson. "But it's been the biggest growth area in the industry."

Although today you'll rarely find trumpets, shimeji or hen of the woods at mainstream groceries, at some Asian markets such as in Honolulu's Chinatown, they are year-round staples, almost as common as buttons. And for a specialty ingredient, they're surprisingly inexpensive — usually less than $10 a pound.

As is common with mushrooms, each of these specialty varieties may be found under several names.

The king trumpets are called king eryngii, or king oysters (technically they're Pleurotus eryngii and are closely related to the common oyster mushroom, P. ostreatus). King trumpets are almost all stem and are large — commonly 3 or 4 inches long and sometimes 6 or 7. Their texture is firm and meaty, and their flavor is mild.

Shimeji (Hypsizygus marmoreus or tessulatus), also called beech mushrooms, look like oversize enoki. However, whereas the latter are cute but basically flavorless, shimeji have a delicious nutty taste. They come in either white or brown.

Perhaps the most deeply flavored of these mushrooms is the hen of the woods or maitake (Grifola frondosa). Although it isn't as attractive as the king trumpet or shimeji — it pretty much looks like something you'd find sprouting from the forest floor — it has a robust earthy, woodsy flavor that is superb.

You can find these mushrooms in Hawai'i at Japanese grocery stores such as Marukai, said food pundit Walter Rhee, who leads Chinatown tours, though he said he doesn't think the supply of these Japanese-style mushrooms is abundant.

"Mushrooms in Japanese cooking are more as a condiment," Rhee. "You don't go hog-wild with mushrooms but use them as a supplement to induce flavor."

More than 95 percent of the mushrooms sold in the U.S. are from the agaricus family, whether they are common white or brown buttons, the slightly larger cremini or the huge portobello. In reality, those are all very closely related mushrooms harvested at various points in their growth.

Agaricus mushrooms are popular because they are easy to grow. While most plants grow in the earth, mushrooms are grown on different bases, called substrates. Agaricus will thrive even on straw.

Other mushrooms, such as oyster and shiitake, grow on dead logs, making them only a little more difficult to cultivate. The specialty mushrooms Hokto is growing take that a step further, growing on a specially composed substrate — primarily sawdust, ground corncobs, and wheat and rice bran.

The holy grail of fungus culture is the cultivation of such treasured wild mushrooms as chanterelles, porcini, morels and truffles. Although experiments are ongoing and hope springs eternal, this is an exceedingly difficult process, because these are mycorrhizal mushrooms. That means they grow only in community with the root systems of living trees, something that is much harder to manage on a commercial scale.

Hokto's plant is at the end of a valley in San Marcos, Calif., that looks like it has seen better days. You approach the building on a dusty road. Then you make a turn, and there it is: metallic white and gleaming in the sun.

It's huge — 250,000 square feet spread across two floors. And it's hugely expensive. Although the company won't talk about spec-ifics, officials acknowledge that by the time everything is up and running, it will have cost at least $50 million.

The operation is terrifically ambitious, even for Hokto, a company that has 25 mushroom-growing facilities in Japan. There, each operation grows one kind of mushroom, either maitake, shi-meji or king trumpet. Here, it will be all three.

In its rough outlines, the process is similar for all the mushrooms, but each type requires its own set of specific circumstances including temperature and humidity, and will have its own zone in the new building.

From the mixing of the substrate to harvesting and packaging, the process is entirely automated, and the mushrooms are never touched by human hands. They are grown in plastic bottles, following a technique developed by Hokto in Japan (they switched from glass after the 1964 Niigata earthquake).

The bottles are first filled with the substrate, which is then inoculated with mushroom culture. Over a period of weeks, this creates a root system called mycelium in the bottle and eventually, given the right conditions, that root system begins to produce mushrooms. Depending on the variety, this can take from 1 1/2 to two months for maitake and king trumpet to more than three months for shimeji.

All the mushrooms will be certified organic. The spent substrate, already mostly recycled material but afterward enriched by the mycelium, will be recycled for animal feed and other agricultural uses. The bottles will be reused for the next crop. The only waste product will be distilled water used in sterilization.

The first year's production goal is ambitious: 4 million pounds. To do that, Anderson says, the companies are going to have to break out of their old markets and into the mainstream.

That could be a challenge in a country where mushroom-eating has always been a little outside the mainstream (Anderson describes the U.S. as "mycophobic").

One thing that should work in these specialty mushrooms' favor is their rich flavor. Not long ago, portobellos went from being a grower's mistake (they're actually just over-mature creminis) to being one of the hottest items in the produce section because of their meaty taste.

These mushrooms have the same potential. Although they won't begin appearing in great numbers until early next year, they can be found in Asian markets.

As with any mushroom, high heat when cooking is the key to getting the best taste. Mushrooms are very high in moisture, and it takes that kind of temperature to concentrate the juices and begin the browning process.

This is particularly true of the shimeji and maitake mushrooms, which need to be cooked well to get the best taste.

Although their flavors are different in nuance, they can be used interchangeably.

Where they really differ is in appearance. So if you're going to be cooking something for which the mushrooms need to look nice — such as the topping for the halibut baked in parchment — the shimeji are a better choice.

On the other hand, the maitake mushrooms, although cosmetically disadvantaged, have a rich, woodsy flavor.

Use them for dishes in which looks aren't so important — pureed in a soup for example, or as a filling for lasagna or crepes.

King trumpets are the only ones of this group that are good raw, and they are very good indeed, with a meaty texture and mild, slightly briny flavor.

Cooking them doesn't seem to improve the flavor much, but they do pick up a nice delicate crust if you sear them well.

Serve these as you would young, firm porcini: Slice them thin (lengthwise so you get the full effect of their size). Strew them across a bed of lightly dressed arugula greens. Shave Parmigiano-Reggiano in long, thin strips over the top and finish with a scattering of toasted pine nuts.

Then take just a moment to revel in the thought that, fairly soon, once-exotic mushrooms may be closer than you think.

Note: The crepe recipe is adapted from the one in Julia Child's "Mastering the Art of French Cooking."

The crepes in the first recipe can be made ahead and stored, tightly sealed with plastic wrap, in the refrigerator, but you must keep waxed paper between them. To reheat, heat the oven to 325 degrees and wrap the crepes in aluminum foil, leaving the waxed paper in between. Place on a cookie sheet in the oven until heated through, about 15 minutes. Remove the crepes from the oven and keep warm in the foil. Don't overcook them or they'll dry out.

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