Lactarius helvus

What You Should Know

Lactarius helvus is a medium-sized or large agaric that has a spicy smell, similar to curry. It has a cinnamon-brown cap, buff gills and excluding colorless, transparent milk. It grows solitary or in scattered groups on the soil.

North American field guides call this mushroom "Lactarius Aquifluus," and often mention the name Lactarius helvus as an outdated, quaint synonym.

In Europe, Lactarius helvus is considered mildly toxic. If large quantities are eaten raw, symptoms can occur. On average it takes 15 minutes to 1 hour for signs of poisoning to appear: These include vomiting, copious diarrhea, and sweating. In Leipzig, Germany in 1949 an estimated 418 people were poisoned by Lactarius helvus.

The possible North American variety has a more salmon to pink color with scant watery milk and a strong smell of maple syrup or caramel.

Other names: Poison Lactarius, Fenugreek Milkcap.

Lactarius helvus Mushroom Identification

1. Ecology

   Mycorrhizal with conifers (rarely with birch) in boggy, wet locations; usually growing in sphagnum; summer and fall; widely distributed and fairly common in northeastern North America from Nova Scotia to Minnesota, but also documented in the southern Appalachians, Texas, Montana, and Idaho.

2. Cap

   3-13 cm; convex with an inrolled margin when young, becoming broadly convex, flat, or shallowly depressed, with an even margin; dry; smooth or finely velvety at first, becoming rough or sub-scaly; somewhat variable in color but usually some version of light brown.

3. Gills

   Attached to the stem or beginning to run down it; close; not infrequently forked near the stem; whitish at first, becoming dirty yellowish as the spores mature but not spotting or staining.

4. Stem

   3-10 cm long; up to 2 cm thick; more or less equal; dry; smooth or very finely velvety when young; without potholes but sometimes with watery spots; very variable in color but frequently orangish, pinkish, or orangish brown; usually with a thin whitish bloom and thus darker were handled.

5. Flesh

   Pale pinkish or pale brownish, becoming dingy with age but not staining on exposure.

6. Milk

   Scant; watery; not staining tissues.

7. Odor and Taste

   Odor (of mature specimens, or on drying) strongly of curry or burned maple syrup; taste mild or slowly, slightly acrid.

8. Spore Print

   Creamy white to pale orangish-yellow.

9. Microscopic Features

   Spores 6-9 x 5-7.5 µ; broadly ellipsoid; ornamentation up to 1 µ high, as amyloid spines and ridges that form nearly complete reticula.

   Pleuromacrocystidia abundant and easily demonstrated on young specimens but often collapsing after sporulation; subcylindric to subclavate or subfusiform; up to about 70 x 12 µ. Cheilocystidia abundant; cylindric to subclavate; frequently septate and/or with slightly encrusted, thick-walled apices. Pileipellis a dense tangle of repent and erect hyaline hyphae 5-10 µ wide.

Lactarius helvus Taxonomy

It was initially described by Elias Magnus Fries in 1821 as Agaricus helvus, before he placed it in the genus Lactarius in 1838. Peck's Lactarius aquifluus has been deemed a synonym. The specific epithet helvus is derived from the Latin for 'honey-yellow'. Its name in German is Maggipilz.

Lactarius helvus Toxicty

Symptoms of poisoning are reported to occur within thirty minutes of consumption, with nausea and vomiting accompanied by vertigo and chills. The toxic agents are thought to be sesquiterpenes. In October 1949, 418 people were poisoned near Leipzig in eastern Germany. The toxins are destroyed by thorough boiling, and the species is used in small quantities as a spice after drying.

The agent which gives the fungus its distinctive odor is sotolon, which also gives fenugreek seed and lovage their characteristic smells. It is present as well in molasses, aged sake and white wine, flor sherry, and roasted tobacco, as well as in maple syrup.

Sources:

Photo 1 - Author: James Lindsey (Creative Commons Attribution-Share Alike 2.5 Generic)

Photo 2 - Author: jensu (Public Domain)

Photo 3 - Author: James Lindsey (Creative Commons Attribution-Share Alike 2.5 Generic)

Photo 4 - Author: Jerzy Opioła (Creative Commons Attribution-Share Alike 3.0 Unported)