Russula

Welcome back to Mushroom Monday, your weekly look at some of PEI’s easy-to-identify fungi. Today it’s not one species, but a group: the Russulas (Russula spp.).

Photo 1: Russulas can be brightly coloured, as with this red-capped species. . .

I confess that classing Russulas as easy-to-identify is a bit misleading. There are hundreds (possibly thousands) of species, and while some can be readily identified many are extraordinarily confusing. My go-to website for mushroom information is Michael Kuo’s mushroomexpert.com. I recommend you check out his entertaining tirade on Russula identification to appreciate the challenges and why matching ‘your’ Russula to a picture and description in a field guide isn’t particularly helpful. 

Photo 2: . . .or more subtle like this green-capped species.

While identifying Russula to species is not a beginner’s game, knowing whether a mushroom is a Russula is satisfyingly easy.  These common PEI fungi are found in a range of habitats from fields to forests to sand dunes.  Caps may be bright yellow, orange or red (Photo 1), or more subtle shades of grey, brown, or green (Photo 2). While this gives a clue to identification for some Russulas, there are easier ways to confirm this group. 

Photo 3: Russula stems are smooth, usually white and brittle - they break like a piece of chalk.

Regardless of colour, under the cap Russulas have gills (rather than folds, pores, or teeth) that are often white or cream-coloured.  Stems are smooth and usually white, making them look a bit like a piece of blackboard chalk (Photo 3, and yes – I know I’m dating myself with that reference!). But the definitive feature for this group of mushrooms is their texture.

Russulas are known as Brittlegills, with good reason: stems and gills are dry, brittle, and snap when you break them. Rub your finger over the gills of mushrooms in this group, you’ll end up with a handful of what looks like slivered almonds (Photo 4). Throw a Russula against the hard ground, a tree trunk, or your friend and it will shatter. 

Photo 4: The brittle gills of Russula species flake like slivered almonds if you run your thumb over them, which is a helpful identification feature.

That brittleness is enough to identify most Russulas.  Fungi in this family have round cells (called ‘sphaerocysts’) rather than the oblong cells of other mushrooms, giving them their unique texture.  There is another group of mushrooms in this family – the Milkcaps – but they have some obvious differences that we’ll look at next week.

Russulas are mycorrhizal fungi that form relationships with plants, including trees such as Spruce, Pine, Hemlock, Larch, Beech, and Oak among others.  They play important ecological roles, and are the fungal partners that allow the beautiful Ghost Pipe (Monotropa uniflora) to exist without chlorophyll (you can read more about that here: https://www.pei-untamed.com/post/ghost-pipe). 

Photo 5: Russulas are a favourite with the Squirrels on my property. This mushroom has been parked in a tree to dry for later storage. You can read more about this Squirrel behavour here:https://www.pei-untamed.com/post/fungivorous-squirrels.

Some Russulas are edible, and you may hear an oft-cited ‘rule’ that if the one you have doesn’t taste spicy or peppery then it’s safe to eat.  The only rule I believe for mushrooms is that they don’t follow rules, and – as a beginner – I don’t eat Russulas unless I know the species, which I usually don’t.  Squirrels don’t follow my rule, and Russulas seem to be among their favorite fungi judging by the numbers they are parking in my Spruce trees to dry for winter storage (Photo 5).

As a group, Russulas are common, ecologically important, and easy to identify parts of PEI untamed!