Mushrooms in Science

A Mushroom that Likes it Dry
by Anna Gerenday

The summer of 2003 was the second driest that I experienced in MN. There were no mushrooms. One day in the middle of summer as I was walking up our driveway, I noticed two small mushrooms growing on a dead branch in the grass under an ash tree (Fraxinus sp.). The mushrooms were orange buff and small, scaly in the center of the cap – nothing familiar to me. I walked on; there were other pressing matters waiting in the house. The image of these mushrooms growing on the dead branch haunted me, and about 5 days later, camera in hand I walked down the hill just in case the mushrooms were still there. They were, though somewhat faded of color. I took a picture showing the striate, scaly cap and another showing the gills. I collected the mushrooms, took a few notes and dried them. Mentally I kept going over the characteristics I noted trying to figure out to what genus they belonged, but I could not could not come up with anything. I completely missed a key character, the serrate gills, which might have jarred my memory.

I looked through every (well, almost) field guide in my library, but found nothing resembling these mushrooms, which by now have joined the pile designated for microscopic study. One day while rearranging my books, I picked up Mushrooms of Colorado by Vera Evenson, and as I quickly flipped through the pages, the image of the orange buff mushroom flashed and disappeared from view. I turned back the pages, and there tit was, the mushrooms, that no other field guide featured: Heliocybe sulcata. I never heard of it, not of the species, not of the genus: “small, furrowed, orangea-brown, scaly cap; white sawtoothed gills; short, whitish stalk with no ring; on old wood” It all fit. Then I read on: “In dry sites in montane ecosystems;” and “look for it in avalanche areas where many aspens are down and decaying. I could accept the “dry” but “montane area”? and “avalanche area”? This was Minnesota, and although I live in a hilly area, there is nothing here that resembles mountains.

There was one more note on the mushroom that was of some importance: this fungus causes brown rot of wood and was removed from the older genus, Lentinus, the members of which cause white rot. I checked How to Know the Gilled Mushrooms by A. H. Smith. It did included Lentinus sulcatus, and provided information very much like the Evenson guide. The implication was that I was dealing with a western species. I entered the name “Heliocybe” on Google, and it almost immediately came back with a site that took me to a distribution map of Heliocybe sulcata in Canada. The map showed that it occurs in Yukon, Alberta, Saskatchewan, Manitoba and even in eastern Ontario saying to me that this was not a western mushroom, but one that is frequently over looked, possibly because of its preference for dry locations. .

Note on the Taxonomy: The correct name of this mushroom is now Lentinus sulcatus”. Whether a fungus causes brown or white rot is not, is not considered a good taxonomic character anymore, because it is not supported by DNA data.

Thanks to Peggy Laine for this info.

Anna Gerenday
geren002@umn.edu

Heliocybe sulcata -- a.k.a. Lentinus sulcatus-- viewed from the top and from the gills.