GROWING GOURMET - Anto2ni.it

416 GROWTH PARAMETERS
nutrified agar media, scierotia form. The Black Morel produces a unique form of sclerotia, whose
sheer numbers run into the thousands per cubic foot. These sclerotia resemble small golden nodules
which eventually amass together. When they are broken during their early stage of development,
many more scierotia grow. Micro-scierotia form abundantly on nutrified, sterilized media, especially
MYA, OMYA and the many variations of these formulas.
When sawdust is inoculated with grain spawn, the scierotia form most abundantly against the glass
or plastic container, or along other interfaces. With most mushroom species producing these unique
formations, sclerotia grow better in darkness than in light. (Heim et al. (1967), Stamets & Chilton
(1983), Volk & Leonard (1990)). Although light can totally inhibit the formation of sclerotia in the
Morchella esculenta group, strains ofMorchella angusticeps are less affected.
Black Morel sclerotia amass as hundreds of small hardened, pumice-like structures which can become
golf-ball sized. The sclerotia-forrning ability is soon lost with continuously expanded
mycelium. Only by using cultures close to their genetic origins is this sclerotia-forming ability preserved.
When the mycelium declines in vigor, scierotia are not only absent, but the mycelium changes
into a mulatto form—cottony white mixed through golden brown, aerial mycelium. When cultures
are transferred for more than ten generations of petri dishes (100 x 15 mm. dishes filled with MYA),
the mycelium ceases to form micro-sclerotia. Clearly, maintaining stock cultures closest to their wild
origins is critical for success in sclerotia production, and by inference, mushroom production.
Morel mycelium adapts to the liquid fermentation (Gilbert (1960) and injection techniques described
in this book and in The Mushroom Cultivator (Stamets and Chilton (1983)). Sclerotia
formation is substantially greater on annual rye grass seed than on coarser grains like rye, wheat or
sorghum. Sclerotia from rye grass seed can be harvested after several weeks of incubation in low light
or darkness.
Suggested Agar Culture Media: MYA, MYPA, PDYA, and OMYA. Volk & Leonard (1990) noted
that Morchella esculenta, when grown on standard media preparations, notably Difco's PDA &
Difco's MycologicalAgar ®, failed to form scierotia spontaneously.
1st, 2nd & 3rd Generation Spawn Media: Rye grain for the first two generations. I prefer using
soaked, annual rye grass seed for the 3rd or final generation, buffered with 5% calcium sulfate (by dry
weight). Mix the rye grass seed and calcium sulfate together in dry form, submerge in water, at 2
times its make-up volume, and allow to sit overnight. Add 5 lbs. of moist hardwood sawdust into
polypropylene bags. Place 1 cup (. 24 liters) of moistened rye grass seed as an even layer to the top
surface of each sawdust-filled bag. Fold bags closed and sterilize for 2-3 hours at 15 psi. Inoculate the
top layer with rye grain or liquid spawn. Do not through-mix. Incubate in low light and/or darkness
for two weeks.
Substrates for Fruiting: When fully colonized and resplendent with sclerotia, take the above and
invert the bags so that the seed layer is on the bottom. Place 4-6 inches of a moist layer of peat moss
that has been buffered with 10% calcium sulfate (by volume) over the Morel seed/sawdust spawn.
This concoction can be placed outside to benefit from natural spring initiation strategies or used in the
attempt to grow Morels indoors. Note that separation of the seed from the substrate is not critical. The
10-12 inch depth from the bottom seed layer to the top surface of the buffered peat moss is sufficient
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