Most mushroom are soft, delicate and sensitive to drying and they don’t care for exposed habitats. They prefer the deep, dark recesses of the forest where there is lots of organic debris that they can use for food and it stays damp for long periods under the canopy. Fungi like it moist.

Wide open grassy places exposed to the sun all day, therefore, are not amongst the favourite spots for fungi to set up shop. There are of course exceptions to every generalization and a handful of fungi have adapted to open spaces. During or after prolonged wet periods, mushrooms will pop up in abundance over lawns and other grassy spots.

Over the years, old clippings and dead roots build up a thatch under grass. This decaying organic matter mixed with soil provides an ideal substrate for a host of microorganisms including fungi. Not only does it supply the food source for energy but thatch tends to hold the moisture for longer which is ideal for the fungus growth. Many fungi can also grow on dead wood. This source becomes available when trees die and the stumps and buried roots under the lawn supply abundant food for a long time for wood decay fungi such as Mica Cap.

To eat or not to eat!

Periodic abundance of mushrooms in grass might attract the eye but don’t go running willy nilly around the neighbourhood harvesting mushrooms. Lots of people these days spray their lawns for white grub, chinch bug , weeds etc. and this results in a number of sprays over the season. So, if your picking on someone else’s turf so to speak then you may also be rewarded by a thin coating of pesticide.

What are mushrooms?

The active phase of a fungus is a very fine thread measured in microns (1 micron = !/1000 mm). It colonizes the thatch or buried wood. When times are right the fungus produces the fruitbodies that we call mushrooms. Mushrooms are amongst Mother Nature’s most prolific, sophisticated and successful spore-producing machines. A good-sized mushroom can shoot off a hundred million spores and hour for days on end. Even the smallest of the lawn mushrooms shoots off spores by the million.

Common Mushrooms Fruiting in Open Grassy Places

Coprinus atramentarius    Tipplers Bane

This mushrooms is conical to bell-shaped and has a smooth, silky, streaked cap with a metallic grey sheen. This inky cap is edible but with a caution. Alcohol must not be consumed with the mushroom or for several days after. The caps contain a substance called coprine which acts like antabuse and, in association with alcohol, gives most unpleasant (but not lethal) symptoms. Flushing over the upper body, metallic taste on the mouth, nausea etc. It fruits in summer and fall.

 Coprinus comatus   Shaggy Mane

Shaggy Mane is one of the "Inky Cap" group. In this group the caps break down rapidly by self digestion (autolysis) to an inky black fluid. Shaggy Mane is a medium sized mushroom that is easily recognized by its tall scaly cap. It is highly prized as an edible by some but it ripens very rapidly to a black inky goo and must be eaten the day it is collected or you will have to suck it through a straw. Shaggy Mane is more common in late fall and more prolific on disturbed sites where it colonizes woody debris.

 Coprinus micaceus    Mica Cap

This is probably one of the most common and widespread of the lawn mushrooms. It grows in old hardwood stumps, dead roots and buried wood. It fruits early in the year, usually in large clusters in grass or soil above the buried wood. The caps are small, tan coloured, radially streaked and when young covered with a layer of tiny mica-like particals that glisten in the morning sum, hence the common name. These delicate flakes often disappear with rain or ageing. This species is edible but the fruitbodies are flimsy and will disappear to almost nothing during cooking. Not only that, there are not any rave reports about its flavour!

Agrocybe vervacti  (no common name)

Locally common in Ontario but not as well known elsewhere, this is a distinctive yellow-brown mushroom. The caps are up to 4 cm across. It fruits during wet periods in summer. Edibility is unknown and no one has volunteered to test it but so far as is known no one in Ontario has ever been poisoned by this species.

Agrocybe molesta   Cracked-Top Agrocybe

Caps 2-5 cm, dry, smooth, becoming cracked and fissured in age, hemispherical to broadly convex, creamy-white to yellowish. Gills attached, close, off-white to dark brown. Stalks up to 8 cm tall by 1 cm broad, coloured as cap. Ring small, sometimes disappearing. Spore print brown. Widespread and common, this brown-spored species fruits in grass. It is also known as A. dura. Not recommended.

Panaeolina foenisecii     Haymaker’s Mushroom

Perhaps the most common of the lawn mushrooms, this species comes up early in the year scattered or in small groups. It is recognized by its small, hemispherical cap and mottled gills. The caps often change colour from darkish brown to light tan as they dry. The spores are black and will leave black smudges on the fingers if the gills are handled. This small mushroom is only one to three centimetres in diameter. It is reported as poisonous because it contains very small amounts of the hallucinogenic psilocybin chemical.

Conocybe lactea     Dunce Cap

This species is only a few centimetres across at best. The cap is cone-shaped, whitish to cream or pale tan. The gills are whitish at first but turn reddish brown as the spores mature. Dunce cap is quite common in grassy spots in around the Great Lakes. It is one of the first mushrooms of the season and fruits solitary or in scattered groups in early summer.

Leucoagaricus naucina      Smooth Lepiota   

One of the larger "grass" mushrooms, the Smooth Lepiota can be up to 10 cm across or more. The cap is hemispherical to convex with a central knob. The gills are white at first but become pale pinkish in age. The stalk is stout and swollen at the base and has a narrow ring. This edible species is never recommended because it is very similar to the deadly poisonous Destroying Angel which has already killed a number of Canadians over the years. It fruits in summer and fall and is especially common on newly developed grassy areas.

Marasmius oreades     Fairy Ring Mushroom

The word "choice" is often overused and overstated for wild edibles of all types. Have you ever chewed on dandelion leaves! For the most part wild mushrooms aren’t as flavourful as the gourmets tell us. The Fairy Ring Fungus, however, is an exception and is one of the better tasting edible mushrooms. This knowledge won’t do you a lot of good in Ontario, however, as the Fairy Ring fungus is not that common in this province. In the west, on the other hand, Marasmius oreades is abundant and is also a serious problem and very destructive of turf grasses. It fruits in rings hence the common name. More important in dry weather it shrivels up but with heavy dew or during rainy weather it resurrects itself and starts to sporulate again. You can collect this fungus wet or dry and shriveled up If it is dry and it is put in water, it will flesh out and look just like "new". If it doesn’t do this you’ve made a mistake and it isn’t the Fairy Ring Mushroom!

Agaricus edulis (= A. bitorquis)        Sidewalk Mushroom  

This is a medium-sized fleshy mushroom and is related to the meadow mushroom that is very similar but prefers more open grassy areas. It is also very close to the commercial mushroom that you buy in the store. The gills are pinkish in young mushrooms but rapidly turn to a dark chocolate brown and even blackish brown. The stalk is stout with a well developed ring on the stalk. It grows in or near hard-packed ground such as cart paths. It is reported as edible and very good and will be very similar in flavour (but better!) to its commercially produced cousin.

Next time you’re wandering around fields and meadows or the local golf course and it’s a slow day keep your eye open for one or other of these common mushrooms. You don’t have to eat them! You can enjoy them as one of nature’s little wonders. If the worst comes to the worst you can always practice your swing on a Conocybe or a Panaeolina and impress your friends with your knowledge of the names. Sadly for some, the hallucinogenic mushrooms of the Psilocybe genus (magic mushrooms) that are so common on the east and west coasts of Canada do not seem to thrive in the central regions. C’est la vie!

Coprinus plicatilis Japanese Parasol

The common name of this species is well-earned.  The fruitbody has the delicate beauty of a Japanese parasol.  In the picture you can see the concertina-like grooves that give the species name 'plicatilis' (= folded).    The fruitbodies spring up overnight and are best seen in early morning while the dew is still on the grass.  They are often frizzled before lunchtime.

Stropharia hardii

This collection of Stropharia hardii is was found on the lawn in the ornamental area of the University of Guelph arboretum.  It is not very common in our area on regular urban lawns although apparently widely distributed east of the Great Plains.    It resembles an Agaricus  but the gills are attached to the stem and are purple-gray or purple-brown.     The cap is smooth, dry  and yellowish.

Other Lawn Fungi in Ontario (and other places in Eastern Canada)

Over the years a number of fungi not described above have been found on open lawns and pastures in our area.  These include the following species.   The page number refers to the page in my book on Mushrooms of Ontario and Eastern Canada.

Agaricus campestris p193,  Bovista plumbea p94, Calocybe carnea p255,  Conocybe tenera p211,  Gastrocybe lateritia p212, Lycoperdon curtisii p88, Panaeolus sphinctrinus p205, Physarum cinereum p39,  Volvariella pusilla not inc.