Tom Volk's Fungus of the Month for June 2000

This month's fungus is Lactarius indigo, the indigo milk mushroom.

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Lactarius indigo This month's fungus is Lactarius indigo, one of the most beautiful mushrooms you can find in the woods, It's not particularly common, but is fairly widespread in its distribution. As a member of the genus Lactarius, it produces a milky latex when cut or bruised. Lactarius in fact means "milk mushroom." You may recognize the "lact-" part of the name from "lactose," commonly known as milk sugar. This specimen has been cut and a bit of latex is oozing out, but this species does not normally produce as much latex as some other Lactarius. species, such as Lactarius piperatus, shown below and to the right. In that picture you can see abundant white latex being produced after I cut the gills of the mushroom. The latex is normally stored in special large hyphae called lactifers or lactiferous tubes. Lactarius piperatus -- note the white latex

Some Lactarius are delicious edible mushrooms, but many are poisonous. Lactarius piperatus, as you might guess by its name, is very peppery in its flavor, almost to the point of being bitter. It would take a very strong stomach to eat this mushroom, so I don't recommend it at all. On the other hand, Lactarius indigo is a delicious edible mushroom-- and fun to eat. There are very few blue foods. Even blueberries are not really blue, but purple! Yes I know there's blue Jell-OTM) and blue cereals for kids (for example, the blue diamonds in Lucky Charms TM) now, but there's just one natural blue food that I know -- blue corn! (Thanks to David Grubb of San Diego for pointing this out.) Lactarius indigo is delicious simply sautéed in butter, but the most fun way I have prepared them is in an omelet with or with scrambled eggs. You can guess what this does to the eggs-- it turns them green!! Green eggs are lots of fun to have, especially for kids. You're on your own for the green ham. Maybe you can leave the ham out of the refrigerator until a green mold grows on it....
(before I get emails [or lawsuits] about this, of course you shouldn't try to make your own green ham at home using this method.....)
There are several other blue mushrooms such as Clitocybe nuda,. the blewit. Make sure you read this page for cautions about eating blue mushrooms such as the likely poisonous blue/purple Cortinarius species.
Lactarius paradoxus from MississippiLactarius indigo and something near L. deliciosus There are many other Lactarius species, including one very similar to our fungus of the month. Lactarius paradoxus, shown to the left, is found in the deep south of the United States. I expect to see it on the NAMA foray in Texas this month. It's a member of the same group of Lactarius, with orange, blue or green latex. apparently most of that group are edible. HOWEVER, you should be absolutely sure of your identification to SPECIES before eating ANY mushroom. Lactarius paradoxus tends to have a silvery sheen to the fruiting body, and much more green as it ages. Lactarius indigo can have some green in it as well. I find the two rather confusing. They're certianly very closely related. There are some other beautiful Lactarius species, such as Lactarius deliciosus and Lactarius thyinos, which are both orange. One of them is shown with L. indigo in the picture to the right, which I took in New York at a foray of the Rochester Area Mycological Association many years ago. There are actually three or four orange Lactarius species that are distinguished by the initial color of the latex- and what color the latex turns upon being exposed to the air.
Russulales spores and sphaerocysts So, what would you say if I told you that Lactarius is not very closely related to many other kinds of mushrooms (the Agaricales) ? Its only close relatives are in the genus Russula. Most mycologists even put Lactarius and Russula (along with Bondarzewia, a poroid mushroom, but that's another story) into a different order, the Russulales. The Russulales are all mycorrhizal fungi, which means they have a mutualistic association with the roots of plants, especially oaks and pines. In addition they all look microscopically similar to the picture to the left. They all have amyloid reticulate basidiospores (amyloid means they turn blue in Melzer's reagent, which contains iodine, and reticulate means they have raised ridges on the spores). They also all have sphaerocysts, the large unstained cells shown in the picture to the left. Sphaerocyst is just a fancy name for round cells that are found in the fruiting bodies rather than hyphae (cylindrical filaments) found in the Agaricales. These round cells are physically less stable than hyphae, which is why the Russulales fruiting bodies break apart so easily. It's not a big surprise that molecular systematics (work with DNA) is holding up the Russulales as a separate order, an assertion made by "traditional" mycologists twenty or thirty years ago.

I hope you enjoyed reading about and looking at this month's fungus. Be on the lookout for Lactarius species when you're in an oak or pine forest. They're often very abundant and fun to find. And just maybe you can try some green eggs and ham.

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