page_title: Hydnellum
section_title: Morphology
hierarchical_section_title: Hydnellum / Morphology
caption_attribution_description: Hydnellum ferrugineum ((Fr.) P. Karst.) Location: Zadnja Trenta valley, East Julian Alps, Posocje, Slovenia EC Notes: Lat.: 46.39941 Long.: 13.7013Code: Bot_387/2009-5467Habitat: Mixed wood, predominantly Fagus sylvatica and Picea abies, in shade, protected from direct rain by tree canopies, calcareous ground, average precipitations ~3.000 mm/year, average temperature 6-8 deg C, elevation 990 m (3.250 feet), alpine phytogeographical region.Substratum: Decomposing tree litter and soil among roots of an old Picea abiesPlace: West side of Zadnja Trenta valley, south of ex Fjori farm house, East Julian Alps, PosoÄ%uFFFDje, Slovenia ECNikon D70 / Nikkor Micro 105mm/f2.8
context_page_description: Hydnellum is a genus of tooth fungi in the family Bankeraceae. Widely distributed in the Northern Hemisphere, the genus contains around 40 species. The fruitbodies of its members grow by slowly enveloping nearby bits of grass and vegetation. There is great variability in the form of Hydnellum fruitbodies, which are greatly influenced by environmental conditions such as rainfall and humidity, drying winds, and temperature. They are too tough and woody to eat comfortably. Several species have become the focus of increasing conservation concern following widespread declines in abundance.
  Hydnellum species produce pigments that have been used to dye textiles. Several chemical compounds—some with unique biological activity—have been isolated and identified from the genus.
  One of the better-known species is the unusual pinkish-white Hydnellum peckii, also known as "strawberries and cream" or as the "bleeding tooth fungus" due to the red droplets that appear on the pinkish or whitish fruitbodies. Another species, H. suaveolens, has a strong odor of anise or peppermint.
context_section_description: Hydnellum fruitbodies have caps and stipes, often with indeterminant growth forms, that may grow in spurts and decay over several weeks. Neighboring fruitbodies can coalesce, forming intricately intertwined caps and partially fused stipes. The flesh has a zoned appearance and is fibrous when fresh, but becomes hard and woody when dry. Zones in the flesh reflect differences in growth during periods of low daytime and high nighttime humidity, and give a fairly accurate record of daily growth. The spines are crowded closely together and are typically decurrent (extending down the length of the stipe). Fruitbodies may display a variety of colors, from white to yellow, olive green, shades of orange, light brown, or dark brown in age.
  Spores of Hydnellum are almost spherical to oblong and tuberculate, and are brown in mass. The basidia (spore-bearing cells) are narrowly club-shaped and usually four-spored; there are no cystidia in Hydnellum. Three types of hyphae are found in the flesh of Hydnellum: generative hyphae (thin-walled, not inflated); skeletal hyphae (thick-walled and narrow); and thin-walled gloeoplerous-like hyphae, which stain with methyl blue.
  In conditions of high humidity, several species can form striking colored drops on the actively growing caps: red drops in H. peckii, H. diabolus, H. ferrugineum, and H. cruentum, yellow drops in H. caeruleum, and coffee-colored drops in H. mirabile. The common names of H. peckii reflect its appearance:  "strawberries and cream" and "bleeding tooth fungus". Some Hydnellum species have a mealy odor (e.g. H. mirabile and H. pineticola) similar to freshly ground flour. H. zonatum smells like melilot, while H. suaveolens has a sweet odor resembling anise or peppermint. All are too tough and woody to be edible, and many have an acrid taste anyway.
  Differences between Hydnellum species tend to be more distinguishable in younger specimens. Fruitbody development is greatly influenced by environmental factors such as levels of rainfall, drying winds, and temperature. The blue tooth (H. caeruleum), for example, develops a deeper blue color when it grows during cooler autumn weather.  Optimal growth occurs during periods of frequent light rains and high humidity; if the habitat dries out, growth will stop, but may resume after further precipitation. This intermittent growth affects the fruitbodies of different species to variable extents, leading to large variations in form, surface texture, and color. The morphological variability of fruitbodies and the dependence of their appearance upon environmental conditions has made Hydnellum a difficult group to study. Canadian mycologist Kenneth A. Harrison, who described several new species from North America, noted "[t]he remarkable longevity of individual sporophores of many species and the changes in appearance that occur during the long period of their development have confused all workers studying this group." For example, H. aurantiacum, initially white, becomes in turn shades of orange, rusty-brown, and brownish-black. Its fruitbody initially has a turbinate (cushion-like) shape with a lumpy surface, later becoming flattened to funnel-shaped with a smooth to corrugated surface texture.
  The caps form from the top of the short stipe by the growth and expansion of a blunt margin and later as a thickening of the upper surface. Spines start to form when the cap hangs over the stipe slightly. They are white in many species, but become brown in maturity as the brown-colored spores accumulate on the surface.
caption: Spines of H. ferrugineum
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