 = Hydnellum peckii = 
 
 Hydnellum peckii is an inedible ( though not toxic ) fungus , and a member of the genus Hydnellum of the family Bankeraceae . It is a hydnoid species , producing spores on the surface of vertical spines or tooth @-@ like projections that hang from the <unk> of the fruit bodies . It is found in North America , Europe , and was recently discovered in Iran ( 2008 ) and Korea ( 2010 ) . Hydnellum peckii is a mycorrhizal species , and forms mutually beneficial relationships with a variety of coniferous trees , growing on the ground singly , scattered , or in fused masses . 
 The fruit bodies typically have a funnel @-@ shaped cap with a white edge , although the shape can be highly variable . Young , moist fruit bodies can " bleed " a bright red fluid that contains a pigment known to have anticoagulant properties similar to <unk> . The unusual appearance of the young fruit bodies has earned the species several descriptive common names , including <unk> and cream , the bleeding Hydnellum , the bleeding tooth fungus , the red @-@ juice tooth , and the Devil 's tooth . Although Hydnellum peckii fruit bodies are readily identifiable when young , they become brown and <unk> when they age . 
 
 = = Taxonomy , phylogeny , and naming = = 
 
 The species was first described scientifically by American mycologist Howard James Banker in 1913 . Italian Pier Andrea <unk> placed the species in the genus Hydnum in 1925 , while Walter Henry Snell and Esther <unk> Dick placed it in <unk> in 1956 ; Hydnum peckii ( Banker ) <unk> and <unk> peckii Snell & <unk> Dick are synonyms of Hydnellum peckii . 
 The fungus is classified in the <unk> ( species thought to be descendants of a common ancestor ) <unk> of the genus Hydnellum , a grouping of similar species with the following shared characteristics : flesh that is marked with concentric lines that form alternating pale and darker zones ( <unk> ) ; an extremely <unk> taste ; a <unk> odor ; spores that are ellipsoid , and not amyloid ( that is , not absorbing iodine when stained with Melzer 's reagent ) , <unk> ( not staining with the reagent Cotton Blue ) , and covered with <unk> ; the presence of clamp connections in the hyphae . Molecular analysis based on the sequences of the internal transcribed <unk> DNA of several Hydnellum species placed H. peckii as most closely related to H. <unk> and H. <unk> . 
 The specific epithet honors mycologist Charles Horton Peck . The fungus is known in the vernacular by several names , including " <unk> and cream " , the " bleeding Hydnellum " , the " red @-@ juice tooth " , " Peck 's <unk> " , the " bleeding tooth fungus " , and the " devil 's tooth " . 
 
 = = Description = = 
 
 As in all mushroom @-@ producing fungi , the fruit bodies ( <unk> ) are the reproductive structures that are produced from fungal mycelium when the appropriate environmental conditions of temperature , humidity and nutrient availability are met . Hydnellum peckii is a <unk> hydnoid fungus , meaning that it has a cap atop a stipe ( stem ) , and a form resembling a Hydnum — characterized by a teeth @-@ like hymenium , rather than gills or pores on the underside of the cap . Fruit bodies growing closely together often appear to fuse together ( this is called " confluence " ) . They can reach a height of up to 10 @.@ 5 cm ( 4 @.@ 1 in ) . Fresh fruit bodies <unk> a striking , thick red fluid when they are moist . 
 The cap 's surface is convex to flattened , more or less uneven and sometimes slightly depressed in the center . It is usually densely covered with " hairs " that give it a texture similar to felt or velvet ; these hairs are <unk> off in age , leaving the caps of mature specimens smooth . Its shape varies from somewhat round to irregular , 4 to 10 cm ( 1 @.@ 6 to 3 @.@ 9 in ) , or even as much as 20 cm ( 7 @.@ 9 in ) wide as a result of confluence . The cap is initially whitish , but later turns slightly brownish , with irregular dark @-@ brown to nearly black blotches where it is <unk> . In maturity , the surface is fibrous and tough , scaly and jagged , grayish @-@ brown in the upper part of the cap , and somewhat woody . The flesh is a pale pinkish @-@ brown . 
 The teeth are slender , cylindrical and <unk> ( <unk> ) , less than 5 mm ( 0 @.@ 20 in ) long , and become shorter closer to the cap edge . They are crowded together , with typically between three and five teeth per square millimeter . <unk> @-@ white initially , they age to a grayish @-@ brown . The stem is thick , very short , and often deformed . It becomes bulbous where it <unk> the ground , and may root into the soil for several centimeters . Although it may reach up to 5 cm ( 2 @.@ 0 in ) in total length , and is 1 to 3 cm ( 0 @.@ 4 to 1 @.@ 2 in ) wide , only about 0 @.@ 1 to 1 cm ( 0 @.@ 0 to 0 @.@ 4 in ) appear above ground . The upper part is covered with the same teeth found on the underside of the cap , whereas the lower part is hairy and often <unk> debris from the forest floor . The odor of the fruit body has been described as " mild to disagreeable " , or , as Banker suggested in his original description , similar to <unk> nuts . 
 
 = = = Microscopic features = = = 
 
 In deposit , the spores appear brown . <unk> them with a light microscope reveals finer details of their structure : they are roughly spherical but end abruptly in a small point , their surfaces are covered with small , <unk> @-@ like <unk> , and their size is between 5 @.@ 0 – 5 @.@ 3 by 4 @.@ 0 – 4 @.@ 7 µm . The spores are in amyloid , meaning they do not absorb iodine when stained with Melzer 's reagent . 
 Hydnellum peckii 's cells ( the hyphae ) also present various characters useful for its characterization . The hyphae that form the cap are hyaline ( translucent ) , smooth , thin @-@ walled , and 3 – 4 µm thick . They collapse when dry , but may be readily revived with a weak ( 2 % ) solution of potassium hydroxide . Those in the cap form an intricate tangle with a tendency to run <unk> . They are divided into cellular compartments ( <unk> ) and have clamp connections — short branches connecting one cell to the previous cell to allow passage of the products of nuclear division . The basidia , the spore @-@ bearing cells in the hymenium , are club @-@ shaped , four @-@ spored , and measure 35 – 40 by 4 @.@ 7 – 6 µm . 
 
 = = = Similar species = = = 
 
 Hydnellum diabolus ( the species epithet is given the <unk> <unk> in some publications ) has a very similar appearance , so much so that some consider it and H. peckii to be synonymous ; H. diabolus is said to have a <unk> pungent odor that is lacking in H. peckii . The differences between the two species are amplified in mature specimens : H. diabolus has an irregularly thickened stem , while the stem of H. peckii is thickened by a " definite <unk> layer " . Additionally , old specimens of H. peckii have a smooth cap , while H. diabolus is <unk> . The related species H. <unk> also <unk> pink droplets of liquid when young and moist . Commonly found growing under conifers in northeastern North America , H. <unk> tastes " unpleasant " , but not acrid . Fruit bodies tend to grow singly , rather than in fused clusters , and , unlike H. peckii , they do not have bulbous stems . 
 
 = = Ecology = = 
 
 Hydnellum peckii is a mycorrhizal fungus , and as such establishes a mutualistic relationship with the roots of certain trees ( referred to as " hosts " ) , in which the fungus exchanges minerals and amino acids extracted from the soil for fixed carbon from the host . The subterranean hyphae of the fungus grow a sheath of tissue around the rootlets of a broad range of tree species , in an intimate association that is especially beneficial to the host ( termed ectomycorrhizal ) , as the fungus produces enzymes that <unk> organic compounds and facilitate the transfer of nutrients to the tree . 
 The ectomycorrhizal structures of H. peckii are among a few in the Bankeraceae that have been studied in detail . They are characterized by a <unk> mantle — a layer of tissue made of hyphae tightly arranged in a parallel orientation , or palisade , and which rarely branch or overlap each other . These hyphae , along with adhering mineral soil particles , are embedded in a gelatinous matrix . The hyphae of the ectomycorrhizae can become <unk> , an adaptation that helps the fungus tolerate unfavorable conditions . <unk> of H. peckii have a peculiar structure — markedly distinct from those of other Bankeraceae — with thick , smooth inner walls and an outer wall that is split <unk> into warts . The most striking characteristic of the ectomycorrhizae as a whole is the way the black outer layers of older sections are shed , giving a " <unk> appearance " . The majority of the underground <unk> of the fungus is concentrated near the surface , most likely as " mycelial mats " — dense clusters of ectomycorrhizae and mycelium . The mycelium is also known to extend far beyond the site of the fruit bodies , as far as 337 centimeters ( 11 @.@ 1 ft ) away . 
 Molecular techniques have been developed to help with conservation efforts of <unk> hydnoid fungi , including H. peckii . While the distribution of the fungus has traditionally been determined by counting the fruit bodies , this method has a major drawback in that fruit bodies are not produced consistently every year , and the absence of fruit bodies is not an indication of the absence of its mycelium in the soil . More modern techniques using the polymerase chain reaction to assess the presence of the fungal DNA in the soil have helped alleviate the issues in monitoring the presence and distribution of fungi mycelia . 
 
 = = Habitat and distribution = = 
 
 The fruit bodies of Hydnellum peckii are found growing solitary , scattered , or clustered together on the ground under conifers , often among mosses and pine needle litter . H. peckii is a " late @-@ stage " fungus that , in boreal forests dominated by jack pine , typically begins associating with more mature hosts once the canopy has closed . A preference for mountainous or subalpine ecosystems has been noted . 
 The fungus has a wide distribution in North America , and is particularly common in the Pacific Northwest ; its range extends north to Alaska and east to North Carolina . In the Puget Sound area of the U.S. state of Washington , it is found in association with Douglas @-@ fir , fir , and hemlock . Along the Oregon Coast it has been collected under lodgepole pine . In addition to North America , the mushroom is widespread in Europe , and its presence has been documented in Italy , Germany , and Scotland . The species is common in the latter location , but becoming increasingly rare in several European countries , such as Norway , The Netherlands , and the Czech Republic . Increased pollution in central Europe has been suggested as one possible factor in the mushroom 's decline there . Reports from Iran in 2008 and Korea in 2010 were the first outside Europe and North America . 
 
 = = Uses = = 
 
 Although the fruit bodies of H. peckii have been described as resembling " Danish pastry topped with <unk> jam " , and Hydnellum species in general are not known to be poisonous , they are inedible due to their extremely bitter taste . This <unk> persists even in dried specimens . 
 The fruit bodies of this and other Hydnellum species are prized by mushroom <unk> . The colors may range from beige when no <unk> is used , to various shades of blue or green depending on the <unk> added . 
 
 = = Chemistry = = 
 
 <unk> of an extract of Hydnellum peckii revealed the presence of an effective anticoagulant , named <unk> ( 2 @,@ 5 @-@ <unk> @-@ 3 @,@ 6 @-@ <unk> ( 4 @-@ <unk> ) <unk> @-@ <unk> ) , and similar in biological activity to the well @-@ known anticoagulant <unk> . <unk> also possesses <unk> activity , inhibiting the enzyme <unk> @-@ <unk> carrier protein <unk> ( essential for the <unk> of fatty acids ) in the bacteria <unk> <unk> . 
 Hydnellum peckii can <unk> the heavy metal caesium . In one Swedish field study , as much as 9 % of the total caesium of the topmost 10 cm ( 3 @.@ 9 in ) of soil was found in the fungal mycelium . In general , ectomycorrhizal fungi , which grow most <unk> in the upper organic <unk> of the soil or at the interface between the organic and mineral layers , are involved in the retention and cycling of caesium @-@ 137 in organic @-@ rich forest soils . 
 
 