Hydnellum scrobiculatum
Hydnellum scrobiculatum, commonly known as the rough hydnellum or ridged tooth, is a tooth fungus in the family Bankeraceae. Widely distributed in the Northern Hemisphere, it is found in Eurasia and North America.
Taxonomy
The fungus was first described as a species of Hydnum by Elias Magnus Fries in his 1815 work Observationes mycologicae. Petter Karsten transferred it to the genus Hydnellum in 1879. Canadian mycologist Kenneth A. Harrison published the variety H. scrobiculatum var. zonatum as a new combination in 1961, but this is now considered to be synonymous with Hydnellum concrescens. Common names given to the species include "pitted corky spine fungus", and the British Mycological Society recommended name "ridged tooth".Description
The fruitbodies have centrally depressed caps measuring in diameter. These caps can fuse together to form concrescent fruitbodies. The caps have wavy edges, and an initially felty surface that becomes scaly with age. Young fruit bodies are white, then pinkish-brown, then purplish brown, sometimes with white margins. The fruitbodies can become shiny in age.The spines on the cap underside are up to 4 mm long. They are initially white, but become purplish brown in maturity. The spines are decurrent—they run down the length of the stipe. The stipe, which is roughly the same color as the cap, measures long by thick. Mycelium at the base of the stipe envelops and grows around forest litter. The flesh smells mealy. The edibility of the fruitbody was previously unknown, but Roger Phillips calls it "poor". In general, Hydnellum species are too acrid and woody to be palatable.
Like all Hydnellum species, H. scrobiculatum produces a brown spore print. Individual spores have a more or less spherical shape, with dimensions of 5.5–6.5 by 4–5.6 μm. They have wart-like projections on the surface. The basidia are narrowly club-shaped, four-spored, and measure 23–29 by 5–6.5 μm.