#173: Lepiotoid Mushrooms

The lepiotoid mushrooms are a genetically diverse group but are often lumped together in field guides to simplify identification. Morphologically, lepiotoid mushrooms most closely resemble mushrooms from the genus Amanita (FFF#172). Lepiotoid mushrooms have free gills, a white spore print, and a partial veil, but are saprobic and lack a universal veil. Despite these shared characteristics, lepiotoid mushrooms have multiple origins. “Lepiotoid” means “like Lepiota.” Most lepiotoid mushrooms were at one time placed in the genus Lepiota, so that genus is used as a basis for this morphological group.¹

Description

Like the amanitas, the lepiotoid mushrooms are agarics with a central stipe and a circular pileus. These mushrooms are generally smaller and thinner than the amanitas, so they are sometimes called “parasol mushrooms.”²

The most important feature of the lepiotoid group is the white spore print. All lepiotoid mushrooms have a white spore print, except for the green-spored Chlorophyllum species.^1,2 The white spore print is really the defining feature of the group. Many lepiotoid genera have the prefix Leuco– in their name, such as Leucoagaricus. Leuco– means “white”³ and when used in a genus name it usually refers to the spores. Consequently, Leucoagaricus describes a genus of white-spored mushrooms that otherwise look like mushrooms from the (dark-spored) genus Agaricus.

To properly identify a mushroom, you should always take a formal spore print. However, this is sometimes not necessary if you’re doing a quick ID in the field or are just looking for a place to start on a key. If you’re too lazy to take a spore print, you can look at the color of a mature mushroom’s gills instead. Most lepiotoid mushrooms have white gills that will remain white until the mushrooms begin to decompose. Other lineages in the Agaricaceae have dark spores, so their gills will turn brownish by maturity. Species in the genus Chlorophyllum have gills that start white but become pale green to greenish as the mushrooms mature. Because of this, you can guess spore print color only by looking at the gills of mature specimens.

An alternate and more accurate method for estimating spore print color is by looking for spores collecting on nearby surfaces. Leaves or other mushrooms that stick up underneath the mushroom are great places to look. If the mushroom has a ring, collected spores can often be found on the top of the ring. These natural spore prints are very handy, but they rarely form.

Another feature that distinguishes the lepiotoid mushrooms is their free gills. This means that the gills radiate out from the stipe but never quite touch the stipe.^1,2 In some lepiotoid mushrooms the gills clearly leave a space around the stipe while others get much closer. Sometimes it can be hard to verify whether a mushroom has free gills and it may come down to a judgment call whether the gills are “free” or “narrowly attached.”

Lepiotoid mushrooms also produce a partial veil. The partial veil is a membrane that protects the developing gills as the mushroom grows. Once the gills are ready to produce spores, the partial veil breaks away. This often leaves evidence hanging around the stipe or along the pileus margin. Remnants around the stipe are called a “ring” or “annulus” and are commonly found in the lepiotoid mushrooms. However, these remains are very fragile and the ring can easily disappear completely or be lost during transport.^1,2,4

Unlike the amanitas, lepiotoid mushrooms do not produce a universal veil. The universal veil is a membrane surrounding the entire mushroom before it fully develops. Because they do not have this veil, lepiotoid mushrooms never produce a volva and never make warts or patches. However, some lepiotoid mushrooms do form squamules on the pileus. Squamules are scale-like bits of tissue that stick up off their surface and are often a different color. At first glance, squamules may seem to be warts. But unlike warts, squamules are attached to the pileus and will peel some of the pileus back when you try to remove them.^1,2,4

Finally, most lepiotoid mushrooms are saprobic, meaning they decompose dead organic matter. Consequently, lepiotoid mushrooms usually grow in places such as: mulch, leaf litter, and large patches of grass. Amanita species, on the other hand, are usually mycorrhizal and grow from the soil under trees.¹

If you still can’t tell whether you’ve picked an Amanita or lepiotoid mushroom, there is one last thing you can check. Take a thin slice of gill tissue (cut perpendicular to the gill face from top to bottom so that it makes a tall V shape) and examine it under a microscope. Lepiotoid mushrooms have disorganized hyphae in the center of their gills, while amanitas have hyphae that point down and out from the middle.²

Edibility

Within the lepiotoid mushrooms, edibility is a mixed bag. The group contains good edibles such as Macrolepiota procera, mushrooms with gastrointestinal irritants such as Chlorophyllum molybdites, and amatoxin-containing mushrooms such as Lepiota castanea (see FFF#091 for more on the deadly amatoxins).² Because lepiotoid mushrooms have many look-alikes and are difficult to identify down to species,¹ I recommend you avoid eating lepiotoid mushrooms. If you choose to eat them, make sure you are well acquainted with the edible lepiotoid mushrooms in your area and with all possible look-alikes.

Taxonomy

Mycologists are still sorting out the genetic relationships of the lepiotoid mushrooms. All lepiotoid mushrooms belong to the family Agaricaceae, but they do not form a distinct lineage within that family. For example, a 2011 paper published in Mycologia produced a phylogeny that had Chlorophyllum (green-spored) most closely related to Agaricus (brown-spored), Macrolepiota (white-spored, lepiotoid) most closely related to Lycoperdon (dark-spored, puffball), and Lepiota species scattered all over the place (though a few did sort out into a distinct lineage).⁵ Despite this, field guides often still group the white-spored Agaricaceae species together because it makes the Agaricaceae easier to key out.

Kingdom	Fungi
Phylum	Basidiomycota
Subphylum	Agaricomycotina
Class	Agaricomycetes
Subclass	Agaricomycetidae
Order	Agaricales
Family	Agaricaceae Chevall.6