GLOSSARY

• Mycelium: The fleshy, vegetative body of a fungus. Mycelium is typically white-colored (Figure 1) and is made up of strands of hyphae, which are somewhat analogous to plant roots. Mycelium can be propagated asexually to produce a “clone” of a given fungal species and strain, which is somewhat analogous to how an apple tree can be asexually propagated via grafted cuttings of branches. Mycelium is used to propagate shiitake strains selected for shiitake production, by inoculating a substrate to produce spawn (Figures 2, 3, & 4).

• White rot fungi: A broad group of decomposer (saprotrophic) fungi that are capable of decomposing carbon compounds in non-living wood, most notably lignin, but also cellulose and hemicellulose. Shiitake is a species of white rot fungus (as are other species of cultivated edible mushrooms; see the Basics and Mushrooms pages), and is capable of breaking down the wood of many species of non-living broadleaf trees.

• Mushroom: The fruiting body of a fungus that initially forms from hyphal “knots” in the mycelium and develops to become capable of producing spores.

  • Stem: The support structure of the mushroom cap, which connects it to its substrate (Figure 4).

  • Cap: The umbrella-shaped upper portion of the mushroom that will develop gills on its underside (Figure 4).

  • Gills: Structures that develop on the underside of the mushroom cap which will become capable of producing spores (Figure 4).

  • Veil: A thin membrane of mycelium that forms on the underside of a developing mushroom cap which eventually ruptures as the cap expands to expose the mushroom’s gills (Figure 4).

• Spores: The reproductive cells produced by a fungus, some of which are capable of sexual reproduction and development of a unique strain. Spores are not used by shiitake producers. They are only used in development of novel cultivated mushroom strains by strain developers.

• Strain: An unique expression of a given species of fungi resulting from sexual reproduction (via spores. Strains are selected for desireable carachteristics (see the Strains page), and are propagated asexually (via mycelium) to retain those characteristics. Strain development usually is usually limited to spawn supply companies because there are significant investments that are required to successfully develop new strains and then propagate them up to commercial-scale spawn production.

• Spawn: A friable, granular organic (carbon-based) material (substrate) that has been inoculated with ,and colonized by a specific species/strain of fungal mycelium. With shiitake spawn, the substrate is typically wood sawdust (Figure 2, also see the Inoculation page) or small pegs. Spawn used in shiitake production is usually produced commercially due to the investments required to help maintain strict sanitation measures that work to keep strains pure and uncontaminated by other pest fungi, bacteria, and insects.

• Substrate: The organic material that a fungus both grows on, and consumes. With forest-cultivated shiitake, the substrate is the wood of the log/bolt (see the Timber page); for other types of cultivated mushrooms and applications other than forest-cultivated mushrooms, grain, bran, or straw may also be used as substrate materials.

• Inoculation: The process where a substrate is initially impregnated with the fungus that will eventually grow to colonize it (Figure 2, also see the Inoculation page).

• Bolt: A log that has been inoculated with fungal mycelium via spawn. Typically, bolts used in forest-cultivated shiitake systems are 4-6” in diameter, and 3-4’-long (Figure 1, also see the Basics, Timber, and Management pages).

• Spawn run period: The period of time between inoculation of the substrate and full colonization of the substrate by the fungus (Figures 1 & 2, also see the Management page).

• Laying yard: The forested space where shiitake mushrooms are produced on natural wood log substrates. The laying yard typically consists of spaces for crib stacks, soaking tanks, and A-frame racks (Figure 1, also see the Site page).

• Crib stacks: Stacks of shiitake bolts that are arranged with layers of 6-8 parallell bolts stacked on top of each other, with each layer oriented in a direction perpendicular from the last layer (also see the Site and Management pages. Typically a single crib stack has four layers, accommodating 24-32 bolts depending on bolt size and shape.

• Resting: Anytime a bolt is not actively fruiting. This includes the spawn run period, and all periods in between forced fruitings; bolts that are at rest are often put into crib stacks for resting periods (Figure 1).

• Forced fruiting: A management strategy used by shiitake growers where the fully colonized substrate (bolts in forest-cultivated systems) is immersed in cold water for a period of time to incite a uniform, abundant flush of mushroom production. Forced fruiting mimics a seasonal weather change by rapidly shifting the temperature and moisture levels that the fungus is exposed to (also see the Fruiting & Harvest page). The ability of some strains of shiitake to respond to forced fruiting is a key attribute that increases shiitake’s potential to be produced in a commercially-viable manner.

• A-frame rack: A single beam that is elevated above the ground by two end posts which bolts are diagonally leaned against during shiitake fruiting and harvest (also see the Fruiting & Harvest and Site pages).

• Fruiting tent: A “tent” that is fashioned from a large peice of breathable fabric to encompass an entire A-frame rack and bolts during fruiting. This is a modified version of a “fruiting blanket” which adds insect pest exclusion and additional mushroom protection against excessive drying. (see the Fruiting & Harvest page, Figure 3 & Video 2)

• Mycelial mat: A thick layer of mycelium that develops under the bark of a bolt during spawn run (Figure 3, also see the Fruiting & Harvest Gallery page, Figure 1A & 1C). Mushrooms will eventually develop from this layer of mycelium, highlighting the critical role of the bolt’s bark in facilitating consequent mushroom production.

• Primordia: The earliest stage of mushroom development where small, raised, hyphal “knots” form in the mycelial mat underneath the bark of a bolt (see the Fruiting & Harvest Gallery page, Figures 1A & 1C). Some, but not all primordia will continue to develop into mushrooms.

• Pinning: The stage of mushroom growth where the primordia have developed into a distinct primitive mushroom stem and cap (see the Fruiting & Harvest Gallery page, Figure 1B).

• Harvest ripe: The spectrum of mushroom development stages relative to when the mushroom should be harvested in accordance with a balance of acceptable yield weight and market quality (Figure 4, also see the Fruiting & Harvest page, Figure 5 & Video 2).

• Waxing stage: The stage of mushroom development (relative to harvest ripeness) that begins after pinning into full harvest ripeness stage where the mushroom veil has broken, but the cap remains relatively thick and the cap edge is still turned substantially inward (Figure 4, also see the Fruiting & Harvest page, Figure 5 & Video 2)

• Full ripe stage: The stage encompassing the late-waxing to early-waning mushroom stages, from when the mushroom veil breaks (to expose the gills on the underside of the cap) until just before the point where the mushroom cap edge begins to turn outward and upward (Figure 4, also see the Fruiting & Harvest page, Figure 5 & Video 2).

• Waning stage: The stage of mushroom development beginning at the point within the fully ripe stage when the mushroom cap begins to thin and the cap edge begins to turn downward, until just before the mushroom cap edge begins to turn completely outward and sporulates. (see the Fruiting & Harvest page, Figure 5 & Video 2)

• Sporulation:The stage of mushroom development where the mushroom releases spores from its gills. Sporulation marks the end of the waning stage of harvest ripeness and the beginning of the mushroom becoming overripe to an unmarketable level (Video 1, also see the Fruiting & Harvest page, Video 2).