Agaricus mushrooms or field mushrooms have gills that start of pink or white, then become chocolate brown, colored by the brown spores. They all have gills free from the stem. They have a ring around the stem, and they all grow on the ground where they decompose organic material.

People sometimes confuse Amanitas, which also have free gills, with field mushrooms, a potentially fatal mistake, although Amanitas have white spores, and their gills remain white.

Other field mushrooms appear in the summer and fall, but the spring agaricus comes up in the spring and fall.

Its convex to flat, dry, brownish cap is 2-6 inches wide.

The narrow gills, free from the stem and close together, begin pinkish and soon turn brown. The spore print is blackish-brown.

The whitish stalk, which darkens in age, is 1-2 inches long, 3/8 to 1-1/4 inches thick. A ring, the remnant of the partial veil that covered the gills when the mushroom was very young, encircles the lower stem. This ring has distinct upper and lower edges, accounting for the specific name, bitorquis, which means 2 rings.

The spring agaricus grows on packed ground in urban and suburban areas. Often it's half-buried in the ground.

The spring agaricus comes up in the spring, and again in the fall, in the eastern US, and from late fall to early spring in California.

The meadow mushroom, A. campestris (the closest relative to the commercial mushroom), also a choice edible, is quite similar, but with a single ring; and it never appears in the spring.

The spring agaricus has a flavor similar to its relative, the commercial mushroom, but much more intense. Any cooking method works with this delicious species, which cooks in about 10-15 minutes.

Unfortunately, it becomes infested with insects the day after it comes up, so you have to collect it right away and prepare it the same day. Fortunately, it tends to appear in the same location year after year, spring and fall, after lots of rain.

I live in a garden apartment complex, and found one or two at a time growing outside my door after my fiancé and I moved in. After a year of patient waiting, there were days of torrential rain. A bumper crop appeared, but the day before, the co-op management had treated all the lawns with chemicals, and I had to leave pounds of choice fungi to rot.