Hypsizygus tessulatus identification

About mushroom

Hypsi means "high" or "on high" and zygus means a "yoke" Hypsizygus, then, referring to position
of this mushroom often high in the tree. Ulm- refers to "elm" indicating one of the common substrates for this fungus.

There are commercially grown forms of this mushroom grown and sold in supermarkets and specialist shops, usually referred to as Buna-shimeji syn Hon-shimeji, the Brown Beech Mushrooms, there is a white form called Bunapi-shimeji.

Hypsizygus tessulatus (Bull. ex Fr.) Singer New syn.
Hypsizygus marmoreus Laskapereszke.

Cap 5-15cm across, convex becoming flatter and rather sunken; white to buff yellow, creamy tan or crust brown in the center; moist, smooth, minutely hairy, becoming cracked with scaly patches.

Gills adnexed to sinuate, close to subdistant, broad; whitish becoming cream.

Stem 40-110 x 10-30mm solid, off-center, enlarged toward the base; white; dry, smooth, sometimes hairy.

Flesh thick, firm; white.

Odor mushroomy.
Taste mild.

Spores globose, smooth, 5-7 x 5-7ยต.

Deposit white to buff.

Season September-December . Habitat singly or scattered on old hardwood trees, especially elm, often quite high up. Frequent.
In nature, shimeji are gilled mushrooms that grow on wood. Most often the mushroom is found on beech trees, hence the common name, Beech Mushroom. They are often small and thin in appearance and popular in many nations across the world.


Growing Hypsizygus tessulatus

The groups of mushrooms are harvested before the caps open. The beige caps are a little coarse and are often harvested when they have a diameter of ca. 2 cm, while the fully grown mushrooms can reach a diameter of 7 to 9 cm.

Recommended substrate: 80% hardwood, mixed fine + coarse; 10% cereals; 10% bran.
humidity: 62 %


A delicious species, H. tessulatus falls under the umbrella concept of the Japanese "Shimeji" mushrooms. Firm textured, this mushroom is considered one of the most "gourmet" of the Oyster-like mushrooms. Recently, this mushroom has been attributed to having anti-cancer properties. I ncreasingly better know, this obscure mushroom compares favorably to P. ostreatus and P.pulmonarius in North American, European and Japanese markets.

Mycelial Characteristics: Mycelium white, cottony, resembling P. ostreatus mycelium but not as aerial. Also, the mycelium of H. tessulatus does not exude the yellowish-orange metabolite nor does it form the classically thick, peelable mycelium, two features that are characteristic of Pleurotus species.

Mircroscopic Features: This mushroom produces white spores.

Suggested Agar Culture Media: Malt Yeast Peptone Agar (MYPA), Potato Dextrose Yeast Agar (PDYA), Dog Food Agar (DFA), or Oatmeal Yeast Agar (OMYA)

Spawn Media: The first two generations of spawn can be grain. The third generation can be sawdust or grain.

Substrates for Fruiting: Supplemented sawdust. Good wood types are cottonwood, willow, oak, alder, beech, or elm. The effectiveness of other woods has not yet been established. It seems that straw does not provide commercially viable crops unless inoculated up to 25% of its weight with sawdust spawn.

Yield Potentials: 1/2 lb. of fresh mushrooms per 5 lb. block (wet weight) of supplemented hardwood sawdust/chips.

Comments: A quality mushroom, Buna shimeji is popular in Japan and is being intensively cultivated in the Nagano Prefecture. The only two mushrooms which come close to this species in over-all quality are H. ulmarius or Pleurotus eryngii.

In the same environment ideal for Shiitake (i.e. normal light, CO2 less than 1000 ppm), strains of H. tessulatus produce a stem less than 2 inches tall and a cap many times broader than the stem is long. When the light is reduced and the carbon dioxide levels are elevated, the mushrooms metamorphosize into the form preferred by the Japanese. Here again, the Japanese have set the standard for quality.

In the growing room, abbreviated caps and stem elongation is encouraged so that forking bouquets emerge from narrow mouthed bottles. Modest light levels are maintained (400 lux) with a higher than normal carbon dioxide levels (>2000 ppm) to promote this form of product. From a cultivator's point of view, this cultivation strategy is well merited, although the mushrooms look quite different from those found in nature. This cultivation strategy is probably the primary reason for the confused identifications. When visiting Japan, American mycologists viewed these abnormal forms of H. tessulatus, a mushroom they had previously seen only in the wild, and suspected they belonged to Lyophyllum.

Many of the strains of H. marmoreus cultivated in Japan produce dark gray brown primordia with speckled caps. These mushrooms lighten in color as the mushrooms mature, becoming tawny or pale woody brown at maturity. Most strains obtained from cloning wild specimens of H tessulatus from the Pacific Northwest of North America are creamy brown when young, fading to a light tan at maturity, and have distinct water-markings on the caps. The differences seen may only be regional in nature.

This mushroom does not exude a yellowish metabolite from the mycelium typical of Pleurotus species. However, it has been found that H. tessulatus produces a mycelium-bound toxin to nematodes, similar to that present in the droplets of P. ostreatus mycelium. This discovery may explain why it is not likely to see a nematode infestation in the course of growing Hypsizygus tessulatus.

Given the number of potentially valuable by-products from cultivating this mushroom, entrepreneurs might want to extract the water soluble anti-cancer compounds and/or menatacides before discarding the waste substrate.

Hypsizygus tessulatus photos

More info about Hypsizygus tessulatus mushroom

Stem type:
rudimentary or absent
Grows on wood
Spore colour:
cream or yellowish
Cap type:
Fungus colour:
White to cream
Normal size:
North America
Bunapi-shimeji, Buna-shimeji, Hon-shimeji, Hypsizygus marmoreus, Laskapereszke, buna shimeji, Beech Mushroom
Last modification: 2015-10-27 13:31:56

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