It's time to unravel the mysteries
of the great Genus Agaricus, a group of mushrooms that we all recognize,
but frequently shy away from. The characteristics of the genus
include free gills, chocolate brown spores, the presence of a veil
(ring), medium to large size and a central stalk that separates
easily from the cap. So far so good, but how do we tell the individual
For species identification, we need to rely on our sensitive
noses and our discriminating color perception. Agaricus fortunately
have quite distinctive odors. They may smell of almonds or anise,
have a fungal odor, or emit a very unpleasant chemical smell.
It is important to aggressively stick your nose into the gills
or the crushed flesh of a freshly squeezed mushroom to pick up
the various odors.
The staining reaction that may occur when the stalk and/or cap
is crushed can also be quite distinctive. There may be no color
change at all, or the flesh may change to yellow, amber, red
or reddish-brown in the stalk, the cap or both. It is best to
check for odor and color changes when the mushroom is fresh as
both the smell and the color can fade with time. Agaricus have
prominent veils that are single, double, evanescent, pendant
or sock-like. This genus is known to cause some allergic reactions
in some people. If you have problems with store-bought Agaricus,
then be very cautious when eating wild Agaricus. These are my
rules for eating known and unknown Agaricus.There
seem to be several in Colorado that are edible, but not well
described. So, identification to species is not always possible:
- Do not eat Agaricus that smell like a chemical--i.e.
phenol, library paste, etc. If you are suspicious, but can detect no odor, begin to cook the sliced mushrooms
and then smell the vapors coming from the pan.
- Do not eat Agaricus that stain yellow or amber at the base of the stalk when it is cut vertically.
- Do not confuse the chocolate-spored Agaricus with
the green-spored Chlorophyllum, the white-spored Lepiotas and Amanitas, or the Stropharia with attached gills.
Agaricus are very common in the city, especially on lawns and
in cemeteries and parks where the grass is well watered. The
most common Agaricus include the following, and June seems to
be their favorite month:
- Agaricus campestris: Found in grass.
A short-stalked mushroom with an evanescent veil and bright
pink gills when young. The odor is fungal. Does not stain.
Kid-glove cap. Edible and delicious.
- Agaricus bitorquis: Found in the hard-packed, bare
dirt of bus stops and paths. Makes mushrumps (humps in the
ground caused by mushrooms beneath). Very sturdy mushroom with
a sock-like veil. Fungal odor may show reddish brown discoloration.
Edible and the bugs like it, too.
- Agaricus arvensis: Grows
in grass and is a tall, stately, very large mushroom with a
prominent double, cogwheel veil. It has a distinct, sweet odor
and stains yellow. It is exceptionally delicious and is my
- Agaricus xanthodermis: Grows
in grass and, when young, has a cap the shape of a marshmallow — flat
on top, round on the sides. The top center of the cap usually
has a greyish brown center. The odor is UNPLEASANT, and the
base of the stalk stains instantly yellow when cut. This is
a poisonous mushroom. The medicinal smell will become more
pronounced if the mushroom is cooked. It also tastes bad.
- Agaricus "Ketring
Park": A large, fleshy, heavy,
underground mushroom probably related to A.
grows on the edges of dead grass patches in Ketring Park
in Littleton. It is edible but has a very strong flavor.
No odor but discolors reddish brown.
- Agaricus "Downing
Street": A large, purple-brown,
fibrillose fungi found several times on Downing south of
I-25. It grows in the strip between the street and the sidewalk,
smells bad, and stains dark red. Most likely related to A.
Hondensis and should be considered poisonous.
- Agaricus "Gary
Pickett": A large, delicious
mushroom that grows in Alamo Park in the mulch. Has no odor
and does not stain. Gary Picket swears that he dropped his
domestic mushroom trimmings in the park and that these beauties
were the result.
As the season marches into August and September, the late summer
high country thunderstorms work their magic and the mountain
Agaricus begin to appear. They share the same genus
characteristics of their city relatives — free gills, chocolate
spores, veils and similar staining reactions and odors. Few city
mushrooms are found in the mountains; few mountain mushrooms
are found in the city with the exception of A.
possibly A. praeclarosquamous. In the mountains at approximately
the elevation of Evergreen and above, Agaricus grow
in habitats that have much in common with their city counterparts.
They like open, grassy fields, conifer duff and squirrel middens,
edges, and interfaces between forest and fields. They don't usually
grow in rocky areas, near streams or on the bare dirt of trails.
Remember, they are saprophytic, not mycorrhizal, and need organic
matter on which to grow. They are usually solitary, but may sometimes
grow in groups of two or three.
The most common Agaricus in dark conifer areas is A.
a fungi that stains obviously amber especially on the cap and
smells very strongly of almonds. Edible and a favorite of many,
A. sylvicola, another yellow stainer whose counterpart in the
city is A. arvensis, grows in mixed aspen/conifer and is usually
solitary. It has an anise or licorice odor and is edible.
A. Augustus is a supremely delicious but unfortunately rare
mushroom often grows near paths or in disturbed soil and seems
to enjoy the sun. The cap and the stalk below the veil are covered
with golden brown scales or fibrils. It has a sweet almond smell
and stains yellow.
A. osecanus is a robust fungus of fields and foothills,
shines like a headlight, and is therefore visible at great distances.
It can look like a puffball. The stalk is shaggy below the
veil; it stains yellow, and smells like almond. This is one
very delicious mushroom if you can find it. There is one
bad guy that appears infrequently in the mountains between
7,000 and 9,000 feet usually along roads or in disturbed
earth and in great quantities.
The mushroom, A. praeclarosquamous, has dark grey fibrils
on the cap, stains yellow at the base, smells awful, and looks
mean. This could be the A. "Downing Street" described in June
We occasionally stumble on Agaricus that stain red and have
an almond odor. Once more, we can follow our simple rule: we
may eat with caution any Agaricus that does not smell of chemicals.
The red stainers growing in Colorado include A
A. pattersonae, and A. sylvaticus. All are edible.
Agaricus do not favor lodgepole, but any area with
lots of blue spruce, engelmann spruce or fir is a good place
to look for them; they are big, bold mushrooms and very easy
to find. I like to look in the deep, dark of the woods of the
Chicago Forks area, Guanella Pass Campground, and the campgrounds
on the east side of Berthoud Pass. They can also grow at high
altitude, and I have found some intriguing, though unnamed, collections
in Church Park and the Montezuma area. Most Agaricus are exceptionally
good to eat and may be cooked using any recipe for supermarket
or domestic mushrooms. I prefer to discard the stems because
they are tough and have a peculiar flavor. I have also not found
a good way to preserve Agaricus; they do not dry particularly
well and tend to get flabby when they are frozen. Pickled buttons
are good, but my favorite concoctions include A.
with Fontina cheese and sage and marinated, grilled caps of any
large, edible Agaricus species. Try these big beauties and I
know you will like them.