Scientific name: Ptychoverpa bohemica
Common name: Wrinkled Thimble Cap
(Information for this species page was gathered in part by Julie Flaherty for
Biology 220W (Spring 2004) at Penn State New Kensington)
The wrinkled thimble cap (Ptychoverpa bohemica) is one of the fungal
species referred to as a "false morel" or "brain mushroom." The fruiting body
("mushroom") of this species arises in the spring from an extensive,
soil-dwelling mass of white, cottony mycelia. The mushroom has a rounded,
wrinkled head that may be flesh colored or reddish brown. This head (which can
be 1.5 to 3.5 cm in diameter) sits on a solid, white or cream colored stalk that
can be 4 to 10 cm in height. The mushroom's head has a folded convoluted
surface that resembles the surface of a mammalian cerebrum. These head
convolutions maximize the spore-releasing surface area of the mushroom cap.
Each mushroom is capable of releasing several million spores from these very
short lived, transient fruiting structures. These mushrooms typically grow in
clusters which can be predictably found year after year in the same location.
The mushrooms only persist for a few weeks each season with the timing for their
emergence being influenced by local site conditions and overall climate
patterns. There is a suggestion that global warming is causing these mushrooms
to emerge earlier and earlier in the spring season. The ideal conditions for
mushroom development are moist soils and warm weather. On our Nature Trail, we
observe P. bohemica most typically in mid to late April.
Ptychoverpa bohemica is most often found in or around trees or other
large vegetation typically close to streams or on the edges of forested
ecosystems. It can be seen in both mixed deciduous forests and coniferous
forests throughout the world. Ptychoverpa bohemica is an active
decomposer of dead wood. Its soil dwelling mycelia also form mutualistic
symbioses with the living roots of a number of species of trees (including
American elm, white ash, apple, and tulip poplar). These mycorrhizal fungi
benefit the trees by greatly increasing the water and nutrient absorptive
surface area of their roots. The fungus in turn gains a variety of energy and
nutritional products from its close cellular contacts with the tree roots.
Both tree and fungus may be obligatorily dependent on each other for survival.
The mushrooms of P. bohemica are eaten by a variety of vertebrates
(including white tailed deer, gray squirrels, red squirrels, voles, and
chipmunks) but contain sufficient levels of toxins (including monomethyl
hydrazine) to discourage their use as a human foodstuff. Monomethyl hydrazine is
water soluble and may be leached or boiled out of the P. bohemica
mushroom prior to ingestion. Even traces of this toxin, though, are enough to
cause severe gastrointestinal disorders.
Ptchoverpa bohemica is often found in great abundance in forested
areas that have recently burned. The underground mycelia of this species
apparently are stimulated to produced fruiting bodies after a substantial
ecosystem fire. As the year's pass, however, and as succession re-establishes
the above ground vegetation, the density of P. bohemica mushrooms
declines back to near pre-fire levels. The profusion of these mushrooms in
burned sites is only observed in ecosystems that previously had a well established
population of P. bohemica and there is no indication of preferential
colonization of this species into burned areas.