Introduction to Fungi, Third Edition

GASTEROMYCETES IN THE GOMPHOID PHALLOID CLADE
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Fig 20.7 Gasteromycetes belonging to the gomphoid phalloid clade. (a) The earth star Geastrum triplex.(b)Sphaerobolus stellatus.
Stages of maturation can be seen from left (immature gasterocarp) through the centre (two opened gasterocarps exhibiting glebal
masses) to right (discharged gasterocarp with everted inner cup). (c) The veiled stinkhorn, Phallus indusiatus.This beautiful species is
called ‘queen of mushrooms’ (kinoko no joou) in Japan. (d) The dog’s stinkhorn, Mutinus caninus. (b) reproduced from Webster and
Weber (1999), with permission from Elsevier.Original print of (c) kindly provided by N.Tuno.
to form a star-like arrangement of two cups
fitting inside each other, attached only by the
triangular tips of their teeth (Fig. 20.7b). Within
the inner cup is a single brown peridiole or
glebal mass about 1 mm in diameter. By sudden
eversion of the inner cup, the peridiole is
projected for a considerable distance. Buller
(1933) has given a detailed account of peridiole
discharge. He showed that the peridiole could be
projected vertically for more than 2 m, and
horizontally for over 4 m, with the record
currently standing at 5.7 m (Ingold, 1971, 1972).
The fungus can be cultivated if a peridiole is
placed in a plate of oatmeal agar, and gasterocarps
are produced after a few weeks’ incubation
in daylight on this medium or on chopped
straw saturated with a nutrient solution (Flegler,
1984; Webster & Weber, 1999).
A section through an almost mature, but
unopened, gasterocarp is shown in Fig. 20.8a. The
peridiole is surrounded by a peridium in which
six layers can be distinguished. Three of these
layers form the structure of the outer cup. The
three layers making up the inner cup consist of
an outer layer of tangentially arranged interwoven
hyphae, a central layer of radially elongated
cells forming a kind of palisade, and a thin
innermost layer of pseudoparenchyma whose
cells undergo deliquescence before glebal
discharge to form a liquid which bathes the
gleba and lies in the bottom on the inner cup.
Before the gasterocarp opens up, the cells of the
palisade layer are rich in glycogen, but this is
converted to glucose during ripening (Engel &
Schneider, 1963). Intracellular accumulation of
glucose causes the osmotic concentration of
the cells to rise so that they absorb water and
become more turgid. The swelling of the palisade
layer is restrained by the tangentially arranged
hyphae, and this sets up strains within the
tissues of the inner cup which are only released
by its turning inside out.
Light is necessary for development, and the
opening of the fruit body is phototropic,