Mushroom of the Month – Lactarius rubidus

Lactarius_rubidus_0675_

by Danny Miller

Welcome to the Mushroom of the Month, a new regular feature showcasing a different interesting Pacific Northwest mushroom every month. Our first mushroom has everything you might want: an unusual species, lots of tantalizing look-alikes, relatively common occurance and a delicious reward for finding it.

The most interesting thing about this mushroom can be told by its common name, the “Candy Cap”. It is a dessert mushroom. That’s right, you don’t use this one to make savory dishes or flavour your main course, you eat it for dessert! When it is dried, its odor and flavor become that of maple syrup. Unfortunately, that only happens when it is dried which means when you find it fresh, you usually won’t be able to tell that you found it (although some large patches create a vague maple odor in the air). Sure enough, at least a half dozen species look very much like it. But don’t despair, there are ways for a clever sleuth to figure it out.

There are dozens of Lactarius species here in the PNW, all of them interesting. Lactarius, as you might guess from the name, are mushrooms that bleed a milky substance when damaged. They lactate! This is most easily noticed by breaking the cap and gills and seeing the milk exude from the gills, although often you’ll see milk come out of the stem as well if you break it. Most often the milk is white, but you will commonly find orange or red milk around here, and other colours including blue milk exist in other parts of the country as well!

Looking at one, it is obviously one of our standard gilled mushrooms, with a cap, gills underneath the cap, and a stem. Or is it? DNA studies have shown that Lactarius and its sister genus, Russula, are not related to any other gilled mushrooms. They evolved to look the same by coincidence. Well, honestly, it probably wasn’t a coincidence. There are only so many ways a mushroom can evolve and survive for millions of years, so it’s probably not so surprising that mushrooms in two different orders would develop to be similar. If you know something about biological classification, you’ll remember that organisms in different orders are only quite distantly related indeed, so that gives you an idea of just how unlike regular mushrooms Lactarius really are!

There was actually one clue, discovered many years ago, that Lactarius and Russula were not like other gilled mushrooms. Many of the cells in them are spherical, whereas most mushrooms only have long stringy cells. If you try to break a regular gilled mushroom cap, it will easily break radially (from the center towards the outside), but not across the top of the cap. If you break the stem of a regular gilled mushroom, it will split easily from top to bottom, but breaking it in half will result in very frayed edges. This is because the long stringy fibers run a certain way. However, in Lactarius (and Russula) the presence of spherical cells everywhere helps the mushroom break equally easily in almost any direction you apply pressure. So you can break a piece of the cap off cleanly, or break the stem with an audible snap as if it was a piece of chalk with no visible fraying. Microscopically, the spores that the mushroom uses to reproduce itself are round (instead of the typical elliptical shape) and are covered in warts that turn black in iodine (also unusual). So we’ve suspected for a hundred years or more that something was different about them and it was very interesting when DNA studies were invented that proved it.

Lactarius’ sister genus, Russula, is an interesting story for another day, but they are famous because the hundreds and hundreds of Russula species out there all look very much the same, so with a little practice you can learn to spot one easily. Lactarius, unfortunately, do not all look the same, so you may find yourself breaking every mushroom you find in half for a while to try and see if you were lucky enough to find a Lactarius.

So how do you spot a candy cap? They are small orange mushrooms about 5cm across, whose fresh bodies bleed white milk when broken, and whose stems will break cleanly like chalk. Like most mushrooms, you will usually find them in the fall. The candy caps here on the west coast are called Lactarius rubidus. The east coast has a candy cap too, but it is technically a slightly different mushroom, with a different name, Lactarius fragilis. The east coast and Europe also have yet another candy cap species called Lactarius camphoratus. But regardless of where you are and which candy cap you find, they are practically identical and so it just doesn’t matter.

Unfortunately, to keep the hunt interesting, there are other Lactarius species that look very much the same and can be difficult to tell apart. Some people just pick them all and bring them home and dry them, hoping that the maple syrup smell with come out, and tossing them if it doesn’t. But with a little practice, you can save yourself a lot of time.

Take a look at the photo of the candy cap and some of its lookalikes. The true candy cap has a dry cap that is not usually sticky when wet. The white milk is very watery, looking like fat free milk and not whole milk. The orange colour is kind of dull. And it is seems to be more often found in urban forests and parks than it is out in the wilderness. Lactarius luculentus and Lactarius subviscidus (also called L. subflammeus) are a brighter orange colour and have somewhat sticky caps when wet. The first one tastes slightly bitter after a while and the second one tastes slightly like a hot pepper after a minute or so of chewing. The real candy cap has no bitter or hot taste. (Remember, be careful when tasting mushrooms and never swallow! Always spit it out afterwards). Then there is Lactarius substriatus and possibly another species we call Lactiarius theiogalus, although that is probably not the right name for it (all of the unlabelled mushrooms in the photo). They look even more like candy caps, with a darker or duller orange colour. But the thick white milk they have should give them away as fakes. You can sometimes also tell them by a slightly sticky cap and a slightly hot peppery taste.

Other Lactarius can be confused as well. If your mushroom is more red than orange, or mostly dull brown, or averages larger than 5cm across, it’s probably something else altogether.

If you are lucky enough to find some, here are a few words about how to eat them. You can’t just eat them, they taste like icky low quality mushrooms with a maple flavouring. However, if you grind them up and stir them into a fatty liquid, they will impart a wonderful maple flavour and none of the icky mushroom flavour that might spoil the taste. For instance, you can stir the candy cap dust into cookie batter. My favourite thing to do is make ice cream. All you need is milk and cream and sugar and these mushrooms. Do not use any other ingredients! Stir the candy cap dust in, use an ice cream maker, and you will get strongly flavoured maple ice cream, an unusual experience you will never forget!

To read more about these and other Lactarius, visit my Pictorial Key for Lactiarus at http://alpental.com/psms/PNWMushrooms/PictorialKey/Lactarius.htm
If you have the time and interest, the entire Pictorial Key covers more than 1,500 PNW species, all with colour photos with similar species shown side by side and their differences highlighted. It also includes a lot of other information about mushrooms and their identification. You can browse it online, or even install it on your phone or tablet and use it in the wilderness with no need for cell reception or an internet connection! http://alpental.com/psms

This Pictorial Key is part of a larger free mushroom identification program for the PC and Mac called “MatchMaker”. The entire program can be found here: http://www.matchmakermushrooms.com

Lactarius rubidus and some of its lookalikes:

Lactarius_luculentus-subflammeus_subviscidus-substriatus_rubidus-fragilis