Hericium Erinaceus - Wikipedia

The fruit bodies of H. erinaceus are large, irregular bulbous tubercules. They are 5–40 centimetres (2–15+1⁄2 inches) in diameter[5] and dominated by crowded, hanging, spore-producing spines, which are 1–5 cm (1⁄2–2 in) long or longer.[6][7]

The hyphal system is monomitic, amyloid, and composed of thin- to thick-walled hyphae that are approximately 3–15 μm (microns) wide. The hyphae also contain clamped septa and gloeoplerous elements (filled with oily, resinous substances), which can come into the hymenium as gloeocystidia.

The basidia are 25–40 μm long and 5–7 μm wide, contain four spores each and possess a basal clamp. The white amyloid spores measure approximately 5–7 μm in length and 4–5 μm in width. The spore shape is described as subglobose to short ellipsoid and the spore surface is smooth to finely roughened.[5][6]

Development

It has been observed that H. erinaceus can fruit intermittently for 20 years on the same dead tree. It is hypothesized that H. erinaceus can survive for 40 years.[5] The mating system of H. erinaceus species found in the U.S. was shown to be bifactorially heterothallic.[8]

The monokaryotic mycelium growth of H. erinaceus is slower than dikaryotic growth and only a relatively low percentage of monokaryotic cultures yield fruitbodies. Monokaryotic fruitbodies are also smaller than dikaryotic fruitbodies.[5] The monokaryotic mycelium was found to produce fusoid to subglobose chlamydospores of 6–8 x 8–10 μm size. These spores can stay viable for more than seven years and be stored under anaerobic conditions.[citation needed] Chlamydospore germination requires 30 to 52 hours, with a germination success rate of 32 to 54%.[8]

Spore production is highest at midday, relative to temperature increase and a decrease of relative humidity. Daily trends toward lower relative humidity can favor sporulation, however, levels of relative humidity that are too low do not favor high total spore production.[9]

Mycochemistry

H. erinaceus contains diverse chemicals, including polysaccharides, such as β-glucan, as well as hericenones and erinacines.[3] From its essential oil, 77 aroma and flavor compounds were identified, including hexadecanoic acid (26% of total oil composition), linoleic acid (13%), phenylacetaldehyde (9%) and benzaldehyde (3%), and other oils, such as 2-methyl-3-furanthiol, 2-ethylpyrazine and 2,6-diethylpyrazine.[10] Low concentrations of ergosterol are present.[3]

Many of these compounds, particularly erinacines and hericenones, are able to readily cross the blood-brain barrier to increase their bioavailability in the brain. Erinacines have been shown to have effects on neuroprotection, antioxidant activity and neuroplasticity in the brain.[11]

Similar species

Similar species in the genus include H. americanum and H. coralloides,[7] both found in eastern North America.[12] Additional species with a resemblance include Donkia pulcherrima, Radulomyces copelandii and some within Sarcodontia.[13]