Wood hedgehog

Hydnum repandum

''Hydnum repandum'', commonly known as the sweet tooth, wood hedgehog or hedgehog mushroom, is an edible mushroom with no poisonous lookalikes. A basidiomycete fungus of the family Hydnaceae, it is the type species of the genus ''Hydnum''. The fungus produces fruit bodies that are characterized by their spore-bearing structures—in the form of spines rather than gills—which hang down from the underside of the cap. The cap is dry, colored yellow to light orange to brown, and often develops an irregular shape, especially when it has grown closely crowded with adjacent fruit bodies. The mushroom tissue is white with a pleasant odor and a spicy or bitter taste. All parts of the mushroom stain orange with age or when bruised.

A mycorrhizal fungus, ''Hydnum repandum'' is broadly distributed in Asia, Australia, North America and Europe where it fruits singly or in close groups in coniferous or deciduous woodland. This is a choice edible species, although mature specimens can develop a bitter taste. Mushrooms are collected and sold in local markets of Europe, Mexico, and Canada.
Wood Hedgehog (Hydnum repandum)  Australia,Geotagged,Hydnum repandum,Winter

Appearance

The orange-, yellow- or tan-colored pileus is up to 17 cm wide, although specimens measuring 25 cm have been documented. It is generally somewhat irregular in shape , with a wavy margin that is rolled inward when young. Caps grow in a distorted shape when fruit bodies are closely clustered. The cap surface is generally dry and smooth, although mature specimens may show cracking. Viewed from above, the caps of mature specimens resemble somewhat those of chanterelles. The flesh is thick, white, firm, brittle, and bruises yellow to orange-brown. The underside is densely covered with small, slender whitish spines measuring 2–7 mm long. These spines sometimes run down at least one side of the stipe. The stipe, typically 3–10 cm long and 1–3 cm thick, is either white or the same color as the cap, and is sometimes off-center. It is easy to overlook the mushrooms when they are situated amongst gilled mushrooms and boletes, because the cap and stipe are fairly nondescript and the mushrooms must be turned over to reveal their spines. The pure white variety of this species, ''H. repandum'' var. ''album'', is smaller than the main variety, with a cap measuring 2–7 cm wide and a stipe that is 1–3 in long.

The spore print is pale cream. Spores are smooth, thin-walled and hyaline , roughly spherical to broadly egg-shaped, and measure 5.5–7.5 by 4.5–5.5 µm. They usually contain a single, large refractive oil droplet. The basidia are club-shaped, four-spored, and measure 30–45 by 6–10 µm. The cap cuticle is a trichodermium of narrow, club-shaped cells that are 2.5–4 µm wide. Underneath this tissue is the subhymenial layer of interwoven hyphae measuring 10–20 µm in diameter. The spine tissue is made of narrow , thin-walled hyphae with clamp connections.
Hedgehog mushroom edible! Fall,Geotagged,Hydnum repandum,United States,Wood hedgehog

Naming

North American lookalikes include the white hedgehog and the giant hedgehog . ''H. albidum'' has a white to pale yellowish grey fruit body that bruises yellow to orange. ''H. albomagnum'' is large and paler than ''H. repandum''. ''Hydnum umbilicatum'' is smaller, with caps measuring 3–5 cm in diameter, and thinner stipes that are 0.5–1 cm wide. Its caps are umbilicate , sometimes with a hole in the center of the cap, unlike the flattened or slightly depressed caps of ''H. repandum''. Microscopically, ''H. umbilicatum'' has spores that are larger and more elliptical than those of ''H. repandum'', measuring 7.5–9 by 6–7.5 µm. A European lookalike, ''Hydnum rufescens'', is also smaller than ''H. repandum'', and has a deeper apricot to orange color. ''Hydnum ellipsosporum'', described as a new species from Germany in 2004, differs from ''H. repandum'' by the shape and length of its spores, which are ellipsoid and measure 9–11 by 6–7.5 µm. Compared to ''H. repandum'', it has smaller fruit bodies, with cap diameters ranging from 3 to 5 cm wide.

Distribution

''Hyndum repandum'' is a mycorrhizal fungus. The fruit bodies grow singly, scattered, or in groups on the ground or in leaf litter in both coniferous and deciduous forests. They can also grow in fairy rings. Fruiting occurs from summer to autumn. The species is widely distributed in the northern temperate zone, and is one of the most common of the tooth fungi. It has been recorded from Australia, Europe, northern Asia, and North America. In Europe, it has been listed as a vulnerable species in the Red Data Lists of the Netherlands, Belgium, and Germany; Sweden lists it as being of Least Concern.

Habitat

''Hyndum repandum'' is a mycorrhizal fungus. The fruit bodies grow singly, scattered, or in groups on the ground or in leaf litter in both coniferous and deciduous forests. They can also grow in fairy rings. Fruiting occurs from summer to autumn. The species is widely distributed in the northern temperate zone, and is one of the most common of the tooth fungi. It has been recorded from Australia, Europe, northern Asia, and North America. In Europe, it has been listed as a vulnerable species in the Red Data Lists of the Netherlands, Belgium, and Germany; Sweden lists it as being of Least Concern.

References:

Some text fragments are auto parsed from Wikipedia.

Taxonomy
KingdomFungi
DivisionBasidiomycota
ClassAgaricomycetes
OrderCantharellales
FamilyHydnaceae
GenusHydnum
SpeciesH. repandum