#183: The Family Entolomataceae

The Entolomataceae are agarics with pink spore prints, attached gills, and spores with sharp corners or bumps. This family is very diverse and morphology varies widely from one species to the next. The mushrooms range in size from small to large, though most are on the small side. A majority of the Entolomataceae are just boring mushrooms, so they are not collected very often. This is probably just as well, since identifying these mushrooms down to species is a herculean task.

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Description

Entolomataceae mushrooms are very diverse morphologically, even within the genera, so it is impossible in this post to describe all the forms they take with any degree of precision. Visit the links at the bottom of this post if you want to learn more about the morphology of specific groups within the Entolomataceae.

Most Entolomataceae are umbrella-like, with a circular pileus, a centrally located stipe, and gills that radiate out from the stipe. However, some species have an off-center stipe or are pleurotoid (see FFF#180).^1,2

These mushrooms produce gills that are attached, although this is sometimes difficult to verify. In many species, the gills are attached with a deep notch, so they may look like they do not touch the stipe. Other species have gills that break off of the stipe at maturity. In both cases, careful examination of the top of the stipe will reveal vertical lines where the gills attach(ed) to the stipe.¹

The most important identifying feature of the Entolomataceae are their spores. Mushrooms in this family produce pinkish spore prints that range anywhere from gray-pink to pink to brown-pink. More significantly, microscopic examination reveals that these spores have distinctly sharp corners (‘angular’). Angular spores are unique to the Entolomataceae, so finding this feature makes it easy to assign your mushroom to the proper family.^1,2

Spore morphology can also be used to distinguish genera within the Entolomataceae. The genus Entoloma features spores with distinct ridges and pits. In most species, the ridges are completely connected. Certain species, however, produce ridges that sometimes don’t connect on one end. Other Entoloma species have these incomplete ridges but also feature small bumps scattered over the spore surface. Spores of the genus Clitopilus appear lined along the long axis when viewed from the side. These lines are actually grooves, so the spores appear angular when viewed from the end. The least angular spores are produced by the genus Rhodocybe. Instead of regular ridges or grooves, Rhodocybe spores grow distinct bumps. This still ends up looking somewhat angular when viewed on end.^1,3

Most Entolomataceae fungi are saprobic and they primarily decompose leaves, twigs, and other forest litter. As a result, you usually find these mushrooms growing on the forest floor. Of course, there are exceptions to these general rules. The pleurotoid mushrooms in the family appear instead on wood or other mushrooms. Actually, a surprising number of Entolomataceae mushrooms are mycotrophic, meaning they parasitically attack other mushrooms instead of decomposing plant material.¹

Identifying to Species

Thinking of trying to identify your Entolomataceae mushroom below the genus level? Don’t bother. Except for a few charismatic species that key out in field guides, identification of these mushrooms requires a professional level of observational skills and familiarity with mycological literature. In order to successfully identify your mushroom, you will need: a good identification key, multiple specimens of your mushroom at different points in development, a microscope, a color reference sheet, an advanced knowledge of mycological terminology, extensive experience observing morphological features of fungi, and a healthy dose of stubbornness. Unfortunately, there are not many keys (and there are no good keys) to North American species of Entolomataceae. So, if you’re ready for a challenge of your mushroom identification skills, by all means try to put a name to your Entolomataceae mushroom! Otherwise, pinning it down to a genus (or even just the family) will most likely suffice.^1,2

Edibility

There are a few edible species in the Entolomataceae, but most are inedible or poisonous. Given how difficult it is to identify mushrooms in this group to species, it is probably wise to avoid the group entirely. You won’t be missing much.⁴

Similar Species

Numerous other taxa contain mushrooms that produce pink spores. The most notable of these is the genus Pluteus (FFF#184), which can be distinguished by its free gills and its stipe that easily separates from the pileus. Most look-alikes have at least one of the following features: free gills, a ring on the stipe, a cobweb-like partial veil (‘cortina’), or a stipe that readily breaks away from the pileus. No Entolomataceae mushrooms have any of those features. The easiest way to eliminate the remaining similar species is to check for the presence of angular spores. Only the Entolomataceae have angular spores and all Entolomataceae mushrooms have some version of angular spores.¹

Taxonomy

The Entolomataceae is one of the rare groups of fungi that the DNA era left relatively unscathed. DNA evidence from 2009 demonstrated that the family was monophyletic, so the group remains taxonomically relevant today. The genus Entoloma underwent the biggest change. Contrary to the general trend in fungal systematics, mycologists found that Entoloma should include a greater number of species. Prior to genetic assessment, mycologists had split Entoloma into numerous smaller genera based on morphology. However, DNA analysis demonstrated that Entoloma was indeed a large and morphologically diverse genus; many smaller genera were therefore reabsorbed into Entoloma.³

Kingdom	Fungi
Division	Basidiomycota
Subdivision	Agaricomycotina
Class	Agaricomycetes
Subclass	Agaricomycetidae
Order	Agaricales
Family	Entolomataceae Kotl. & Pouzar5