Grifola frondosa

"Ram's Head" redirects here. For the shoe, see pigache. For locations with that name, see Ram Head. For the military skill badge, see Ram's Head Device. For the head of the male animal, see sheep.

Grifola frondosa, also known as hen-of-the-woods, sheep's head,^[2] ram's head, or maitake (舞茸, "dancing mushroom") in Japanese, is a polypore mushroom that grows at the base of trees, particularly old growth oaks or maples. It is native to China, Europe, and North America.

Maitake
Scientific classification
Kingdom:	Fungi
Division:	Basidiomycota
Class:	Agaricomycetes
Order:	Polyporales
Family:	Meripilaceae
Genus:	Grifola
Species:	G. frondosa
Binomial name
Grifola frondosa (Dicks.) Gray (1821)
Synonyms
Boletus frondosus Dicks. (1785) Polyporus frondosus Fr.[1]

Grifola frondosa Mycological characteristics
	Pores on hymenium
	Cap is offset or indistinct
	Hymenium is decurrent
	Stipe is bare
	Spore print is white
	Ecology is parasitic
	Edibility is choice or can cause allergic reactions

It is an edible mushroom long used in East Asian cuisine and studied for its potential health benefits, though no high-quality clinical evidence supports its medicinal use.

Description

Like the sulphur shelf mushroom, G. frondosa is a perennial fungus that often grows in the same place for several years in succession.

G. frondosa grows from an underground tuber-like structure known as a sclerotium, about the size of a potato.^[2] The fruiting body, individually up to 10 centimetres (4 in) across but whole clumps up to 50 cm (20 in),^[3] rarely 150 cm (60 in), is a cluster consisting of multiple grayish-brown caps which are often curled or spoon-shaped, with wavy margins and 2–10 cm (1–4 in) broad.^[4] The undersurface of each cap bears about one to three pores per millimeter, with the tubes rarely deeper than 3 mm (1⁄8 in).^[4] The cream-coloured stipe (stalk) has a branchy structure^[5] and becomes tough as the mushroom matures.^{[citation needed][6]}

In Japan, the maitake can grow to more than 45 kilograms (100 pounds).

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  Close-up
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  Cross-section
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  From Vinnytsia Raion, Ukraine

Similar species

G. frondosa is a very distinct mushroom except for its cousin, the black staining mushroom, which is similar in taste but rubbery. Edible species which look similar to G. frondosa include Meripilus sumstinei (which stains black), Sparassis spathulata^[7] and Laetiporus sulphureus, another edible bracket fungus that is commonly called chicken of the woods or "sulphur shelf". Polyporus umbellatus has distinct roundish caps.^[5]

Distribution and habitat

It is native to China, Europe (August to October),^[3] and eastern North America^[8] (from September to October).^[5]

It occurs most prolifically in eastern North America, but has been found as far west as Idaho.^[2]

Uses

The species is a choice edible mushroom,^[9] especially the young caps when slow cooked, although some may be allergic to it.^[2] The softer caps must be thoroughly cooked.^[4] It can also be pickled.^[2]

Maitake has been consumed for centuries in China and Japan^[10] where it is one of the major culinary mushrooms.^{[citation needed]} The mushroom is used in many Japanese dishes, such as nabemono.^{[citation needed]}

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  Maitake tempura
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  In takikomi gohan
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  With soba noodles

Research

Although under laboratory and preliminary clinical research for many years, particularly for the possible biological effects of its polysaccharides, there are no completed, high-quality Phase III clinical studies for the species as of 2019^[update].^[10][11]

There are reviews of D-faction extracted from Maitake, including completed Phase I/II clinical trial demonstrating that "Treatment with sulfated polysaccharide obtained from Grifola frondosa (S-GFB) resulted in apoptosis of HepG2 cells", and "In a phase I/II trial of breast cancer survivors, Grifola frondosa extract acted as an immunomodulator." Same trial has concluded: "There appears to be no “maximum dose”, only “optimal dose” depending on the immunologic endpoint."

See also

• Medicinal fungi