Deborah B. Shaw's Story Behind the Art

Dog Turd Fungus, Dog Poop Fungus, Dead Man’s Foot, Dyemaker’s Puffball
Pisolithus tinctorius
Pisolithus tinctorius (also known as Pisolithus arrhizus) is commonly described as the least attractive of all fungi. The common names are an apt description: Dog Turd Fungus, or Dead Man’s Foot. Another common name, however, begins to hint at one of the many beneficial qualities of Pisolithus: Dyemaker’s Fungus.
The scientific name is derived from the Greek: “piso” means pea-shaped and “lithos” translates to stone. “Arrhizus” means rootless — or “rootless pea-stone.” It was described in 1786 by the Italian mycologist Giovanni Antonio Scopoli. The tinctorius in the species name refers to its use in dyeing wool; the Italian botanist Pier Antonio Micheli mentioned it as a dye for wool as early as 1729 in his work Nova Plantarum Genera. Wool dyed with P. tinctorius ranges from a warm, deep yellow to a rich, chocolate brown.
In cross-section it’s easy to see the distinctive “peas” or pseudoperidioles, the little compartments where the spores are formed. Each starts out tiny and yellowish at the base of the fungus. They then push up toward the top and expand into distinctive, separate compartments. At maturity the thin walls of the pseudoperidia disintegrate into a fine cinnamon-colored dust (the spores). When young, the pseudoperidiolia look as though they are suspended in black tar, and the fungus is so firm and solid it can push through asphalt! When mature, the outer rind becomes crisp and fragile, disintegrating easily to release the spores. The spores are dispersed through the air, and I can personally attest that the fine cinnamon powder goes everywhere.
P. tinctorius starts out as a ball shape when young, but then grows into bizarre monstrous shapes like stumps or giant molars. The literature states that it can smell foul when mature; my specimens only had a pleasant earthy, mushroom-y scent.
P. tinctorius is an ectomycorrhizal fungus that forms fruiting bodies at the end of our dry season, usually in summer through the fall. It gets its nutrition in a mutualistic association with tree roots — an association that helps trees access scarce nutrients such as nitrogen and phosphate. It inhabits poor and disturbed soils, can withstand drought, high temperatures in the summer, acidic soils and soils contaminated with heavy metals and mine tailings. It is so beneficial to tree growth it is widely used in reforestation projects. In fact, mychorrhizal inoculum mixes that contain P. tinctorius are available for purchase in nurseries. Scientists all over the world are sequencing P. tinctorius and P. microcarpus to better understand the symbiotic relationship with their host trees as well as how they may help to clean up environmental contamination.
P. tinctorius has been shown to form some antibiotic compounds; it has been theorized that one of the ways it aids its host plants is to provide protection against microorganisms that cause disease.
Until recently, all Pisolithus found around the world were thought to be just one species, but DNA research has shown there are at least eleven different types. Some are found only in association with one host tree species, but others, like the P. tinctorius, are not picky. Here in California, P. tinctorius is usually found growing with pines and oaks, but the specimens I painted were associated with the Birch trees in my yard.
DNA analysis has confirmed that Pisolithus is related to the Bolete (like the delicious Boletus edulis, although I wouldn’t try to eat P. tinctorius). 
I was attracted to painting P. tinctorius for the variety of textures. (Full confession: the common name didn’t hurt either.) While painting the outside of the fungus it seemed as though I was painting canyons or the surface of a planet. The cross-section was reminiscent of a slab of agate; a beautiful, flat pattern that was an astonishing surprise, given the outside appearance. I had no idea what I was looking at when clumps of P. tinctorius came up in our yard four years ago, and I relished the humorous and interesting identification and research process. When it came up again this year, well, how much weirder, wilder and wonderful could a specimen be?
  • (C) Deborah B. Shaw