GROWING GOURMET - Anto2ni.it

112 THE STOCK CULTURE LIBRARY
Figure 92. A strain of the Abalone Oyster Mushroom,
Pleurotus cystidiosus. This mushroom species
is dimorphic—having an alternative life cycle path
(see Figure 41). The black droplets are resplendent
with spores and are not contaminants.
asexual stage, promptly discarded the cultures
I gave her because they were "contaminated".
(See Figure 92.)
Mushroom strains, once characterized by
rhizomorphic mycelia, often degenerate after
many transfers. Usually the decline in vigor follows
this pattern: A healthy strain is first
rhizomorphic in appearance, and then after
months of transfers the culture sectors, forming
diverging "fans" of linear, cottony and
appressed mycelium. Often an unstable strain
develops mycelium with aerial tufts of cottonlike
growth. The mycelium at the center of the
petri dish, giving birth to these fans of disparate
growth, is genetically unstable, and being
in an active state of decline, sends forth mutation-ridden
chains of cells. Often times, the
ability to give rise to volunteer primordia on
nutrified agar media, once characteristic of a
strain, declines or disappears entirely. Speed of
growth decelerates. If not entirely dying out, the
strain is reduced to an anemic state of slow
growth, eventually incapable of fruiting. Prone
to disease attack, especially by parasitic bacteria,
the mushroom strain usually dies.
Color: Most mushroom species produce
mycelia that undergo mesmerizing transformations
in pigmentation as they age, from the
youngest stages of growth to the oldest. One
must learn the natural progression of colorations
for each species' mycelium. Since the
cultivator is ever watchful for the occurrence of
certain colors which can forebode contamination,
knowing these changes is critical.
Universally, the color green is bad in mushroom
culture, usually indicating the presence of
Figure 93. Miniature mushroom (Gymnopilus
luteofolius) forming on malt agar media. Note proportion
of mushroom relative to mycelial mat.
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