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Lactarius

Expert links: Coloured Milk Milk that turns Yellow Purple Staining
  Candy Caps, etc. Small Lactarius More Lactarius

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Lactarius are cool. When you break a piece of the cap off of a fresh mushroom (which is especially easy in Lactarius as I will soon explain) or just scratch the gills with a knife, they bleed! This makes it relatively easy to identify a fresh one. If you have a dainty little mushroom that bleeds red, white or clear, then you might have a Mycena, but generally, if it bleeds between the gills and cap flesh, it's probably a Lactarius.

Lactarius

Not Lactarius (too dainty)

Russula is very closely related to Lactarius and believe it or not, they are not closely related to other gilled mushrooms. They are another order of mushrooms altogether, that just by coincidence evolved gills to look like other gilled mushrooms. Well, truthfully, as I explain here, it probably wasn't all that great a coincidence as there are only so many shapes you can make and manage to survive successfully for millions of years. But technically, by one definition: "mushrooms genetically related a certain amount to the typical gilled mushroom, Agaricus", Lactarius and Russula are not gilled mushrooms.

Russula and Lactarius share a very interesting quality... a great deal of their cells are spheres instead of long stringy fibres, so instead of wanting to fray when you break the stem in half, with lots of stringy bits hanging off the two broken ends, they can make a clean break (often with an audible "snap!") in whatever direction you want to break them. (You can see some clean breaks in the L. indigo photo). They don't favour peeling in stripes of fibres down the stem, or peeling in a string from the edge of the cap towards the centre like most other mushrooms. They just don't care how you break them.  (For the other end of the spectrum see Inocybe). Which means if you throw a Lactarius or Russula really hard against a tree (this is more fun than it sounds, trust me) portions of them might just disintegrate into a million tiny spheres instead of leaving a pile of long stringy things behind. It's one of the reasons I sometimes say "I can't tell you what mushroom you have, but I might be able to tell you what mushroom you used to have".

Like Russula, many Lactarius are famous for being hot like jalapeno peppers! This is variously referred to as peppery, acrid or hot. It's a really interesting sensation you might have to get used to if you want to identify them, because many Russula and Lactarius look alike but only differ by one being painfully spicy and one not. And the reaction can be delayed up to a minute or so. You start chewing and chewing and after you're sure nothing is happening, BOOM! Hot! (Just make sure to spit it out). Some Lactarius are said to be poisonous, especially the peppery ones (but that may just be for people with stomachs that are sensitive to that spicy flavour). It's interesting to note that many people of Russian descent eat all Lactarius and Russula they find indiscriminately, but they go through a long preparation of boiling, cooking, pickling etc. for a period of months, and it's entirely possible that something in that long process is removing the "pepperiness" and toxins that can upset your stomach if you do not go through that particular preparation. Like I explain here, the answer to many questions about mushrooms is, "nobody knows!"

Most Russula and Lactarius appear to be mycorrhizal, so you will usually find them on the ground under certain trees, often conifers (unless otherwise stated). The caps may be dry or viscid, but there is never a partial veil. Not hygrophanous. Adnate to decurrent gills. The typical Lactarius has a cap diameter of maybe 5-15cm, if they average smaller or larger, that will be stated. If the mushroom has dried up, it's not going to bleed anymore, so you'll have to actually learn what each one looks like to correctly identify it.

For gastroid (misshapen) and truffle Lactarius, see my page on Gastroid and Truffle Fungi.

Key to Lactarius:

Coloured Milk

First, let's talk about the ones with coloured milk. Be careful: yellow milk is often white milk that quickly changed colour. That is the next section.

Lactarius 'deliciosus' - orange, orange milk - concentric circles on cap, stem with water spots (scrobiculate), turns green as it ages.

Lactarius 'deterrimus' - orange milk that may stain tissues red. It is unclear how many separate species there are, or what they should be called.

L. aestivus - summer to early fall, less inclined to turn green.

L. aurantiosordidus (L. deliciosus var. olivaceosordidus) - southern species, smallish, dingy orange and greenish with spruce.

Lactarius rubrilacteus - red milk, cap not bright. The flesh inside the cap can also turn pure green, not just the outside of the mushroom.

L. barrowsii - similar, but cap almost white. Prefers pine.

Lactarius indigo - blue milk - OK, I admit I'm just teasing you now. This may not occur in the PNW, only back east, but you should know about it. Whoever said there is no such thing as blue food didn't know about this mushroom.

Lactarius 'chelidonium' - blue-green mushroom with yellow latex staining tissues greener.

 

Milk that turns yellow

Just about every other Lactarius around here has white milk. But sometimes, the milk will change colour to yellow. Don't eat these, they are varying degrees of peppery, and some are said to be poisonous.

This happened in 10 seconds!

Lactarius scrobiculatus - Bearded around the cap edge, and scrobiculate stalk (the "water spots" I mentioned for the coloured milk caps).

Lactarius resimus - a whitish bearded relative. Similar to L. pubescens, but not confined to birch, and somewhat scrobiculate.

Lactarius xanthogalactus ('chrysorheus'/'vinaceorufescens') - orange capped. Related to the candy cap, but a bit bigger with a white stem. Southern.

Purple staining Lactarius - This reaction might not happen in under 10 seconds like the milk that turns yellow, but it's pretty quick... just give it a few minutes. Break the cap, and rub the milk on the gills. The milk itself doesn't turn purple, but it turns any part of itself that the milk touches to purple. It won't turn anything that isn't a part of the mushroom purple, and the milk itself won't turn purple. None of these are very peppery. Most are not large (<10cm).

L. pallescens - mostly white. KOH yellow on cap, with a slimier stem than L. montanus.

Lactarius montanus ('uvidus') - greyish cap, sometimes with lilac or orange tints. Resinous taste? KOH green on cap.

L. 'californiensis' - improperly named southern species said to microscopically different.

Lactarius cascadensis - big (>10cm), greyish mushroom with cinnamon gills. Under alder.

Lactarius aspideoides/'aspideus' - smooth and yellow. The milk may turn purple too in some collections.

Lactarius representaneus - big, bearded cap rim and yellow, scrobiculate stem, probably the coolest of the purple staining ones.

 

Candy Caps and lookalikes - orange, small (~5cm cap width, or if larger, the stem will be slender (<1cm wide). (Small red or brown Lactarius are in the next section).

One of the coolest mushrooms of all time is the Candy Cap. It is an amazing dessert mushroom... that's right, it is eaten as dessert. When dried it smells and tastes like maple syrup! It is often used to make cookies and ice cream and if you ate some you would probably not believe that the only flavouring used in these desserts is a mushroom. The problem is, it only smells like that when cooked or dried, and can be very hard to separate from the half-dozen or so lookalikes that also grow around here. Some people resort to picking every small orange Lactarius they find and drying them day after day, year after year until they get lucky. Some people burn them with a lighter to see if they can induce the smell. But there's hope, there are some slight differences.

Lactarius rubidus ('camphoratus'/'fragilis') - Candy cap. Dry, dull cap. The white milk is very watery like skim milk, not thick like whole milk. When fruiting in numbers, the forest may smell of maple, perhaps because the mycelium itself puts out a slight maple scent. The fresh taste is completely mild.

Lactarius subviscidus - Perhaps the deepest orange colours. Subviscid. Tastes slightly hot after a minute of chewing.

Lactarius substriatus (subflammeus) - Caps viscid and somewhat striate? The milk eventually stains itself and tissues slightly yellow. Tastes slightly peppery after a minute of chewing. The hardest to tell apart from a candy cap.

Lactarius luculentus - perhaps the brightest or palest orange caps. Viscid. Tastes slightly bitter after a minute of chewing.

 

Other small Lactarius - ~5cm cap width, or if larger, the stem will usually be slender (<1cm wide).

First are small, reddish brown Lactarius, not quite as orange as the candy cap and its lookalikes. They are almost always dry capped. They are related to the candy cap group.

Lactarius rufus - the largest of the group and the most red. Be careful, this mushroom has the hottest taste of all! Habanero pepper spicy. It is larger than the others, but it's still more slender than most Lactarius and the colours are close to a candy cap but more brick red.

Lactarius occidentalis - mild, only near alder trees which makes it a little harder to find, and the dullest brown colour.

Lactarius obscuratus - much rarer and differs by being slightly acrid and having milk that never starts to turn yellowish, also under alder.

Lactarius atrobadius ('hepaticus') - dark brownish-orange, viscid and mild. The European L. hepaticus, if it occurs here, is dry capped and slightly acrid.

Lactarius alpinus - also under alder, very much like L. occidentalis and the candy cap group but either hard to find or easily confused with something else. Cap sometimes scaly. Some varieties only grow at high elevations.

These small Lactarius are not related to the candy cap group.

Lactarius glyciosmus - grey, with an occasional hint of lilac, prefers birch. Smells just like coconut!

Lactarius lepidotus - small, brown, powdery to scaly on the cap! Described from Mt. Rainier under alder.

Lactarius fallax ('lignyotus') - a gorgeous mushroom with a dry, suede felty cap when young. There are 2 cryptic varieties here, not separated by the occasional gill margination. In a distinct subgenus.

Lactarius pseudomucidus - slimy all over. Distinctive because of the beautiful contrast between dark cap, pure white gills, and dark stem.

 

More Lactarius - up to 10cm or more, but if not, the stems will usually be stocky (>1cm thick).

Lactarius rufus - often >5cm, brick red and the hottest taste of all!

Lactarius necator (turpis)/olivaceo-umbrinus - beautifully ugly dark greenish orange. L. olivaceo-umbrinus is said to have milk that slowly changes greenish and prefers conifers, especially spruce. Lactarius necator doesn't and prefers introduced birch. Peppery.

Lactarius pubescens - a bearded species (hairy cap rim), whose milk doesn't change colour quickly (perhaps slowly yellow). Very pale with a hint of pinkish orange, only found under birch, peppery and inedible.

Lactarius torminosus - related, may be darker orange, also bearded, somewhat concentrically zoned, usually under different hardwoods, peppery.

L. subvillosus - similar orange zoned, somewhat bearded cap, but with a scrobiculate stem. Very peppery. Southern.

Lactarius olympianus - zoned orange cap that is not bearded and the stalk is white. Peppery. See also L. trivialis below, which is milder.

Lactarius alnicola - yellowish, the milk might stain yellow slowly. Usually zoned. Like L. olympianus when orangish. Like L. scrobiculatus when slightly bearded or scrobiculate (which it is related to). Peppery.

Lactarius controversus - BIG, and very pale, usually with nice pink gills. Looks like Russula brevipes except for the pink gills (or Hygrophorus saxatilis). Under hardwoods. Peppery.

Lactarius pseudodeceptivus - without the pink gills, under conifers, said to taste quickly acrid.

L. circellatus var borealis - purplish-grey cap, often zoned. Pale pinkish to orange gills. See also L. trivialis, below.

Lactarius kauffmanii -  related to L. pseudomucidus and viscid all over. There is not such a beautiful contrast between the gills and stem because the stem is paler... only the cap is nice and dark.

L. caespitosus - usually plain grey to olive brown, sometimes clustered. Related to L. kauffmanii.

L. glutigriseus - small southern species (<5cm) also grey-brown, but may have a hint of orange, further confusing things. Only slightly acrid.

Lactarius affinis - cap with orange tones. Northern species. L. olympianus is zoned, and sometimes so is L. trivialis (its relative), which is milder.

L. trivialis - may start out greyish-purple like other species, but develops orange tones in age like L. affinis. Sometimes zoned and rather mild tasting.

L. argillaceifolius var megacarpus - quite large, also purplish-grey, not usually zoned. Gills really stain brown. Southern oak species.

Congratulations! You made it through all of the common (and most distinctive rare) species of Lactarius in the PNW. For specialized literature for those of you who just can't get enough milky caps, get a copy of Bessette et. al. "Milk Mushrooms of North America".

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