Introduction to Fungi, Third Edition

EUAGARICS CLADE
537
psychromorbidus), Coprinellus (e.g. C. bisporus, C.
domesticus, C. heptemerus, C. micaceus, C. plagioporus,
C. sassii), and Parasola (e.g. C. plicatilis). Members of
the genus Coprinopsis produce fruit bodies with
hollow stipes and are closely related to
Psathyrella, thereby presenting the opportunity
to re-name Coprinaceae as Psathyrellaceae.
However, because the old name Coprinus in a
broad sense (sensu lato) continues to be used in
most non-taxonomic studies, we follow that
convention for the time being. It is also possible
that there will eventually be an initiative to
designate a new type-species of Coprinus, i.e. to
change the name C. comatus rather than those of
almost all the other species.
Coprinus sensu lato (c. 350 spp.)
This is the large group of ‘ink-caps’ with
deliquescent inaequi-hymenial gills undergoing
autodigestion at maturity (see Orton & Watling,
1979). Representatives of Coprinus sensu lato
are cosmopolitan, fruiting on a great variety of
substrata including soil, dung and wood (Orton
& Watling, 1979). Coprinus comatus (the shaggy
ink-cap or lawyer’s wig; Fig. 19.14c) fruits on
soil, especially on disturbed ground. It has a
well-developed, moveable annulus. Another characteristic
feature is the presence of an elastic
strand of aggregated hyphae which extends
through the lumen of the hollow stipe
(Redhead, 2001). Basidiocarps of C. atramentarius
(common ink-cap or pavement cracker) emerge
at the soil surface from buried wood; those of
C. micaceus (glistening ink-cap) are found in
similar situations, or directly on broad-leaved
tree stumps. Coprinus domesticus also fruits on
dead wood of deciduous trees arising from a
rust-coloured sporulating mat of mycelium, the
Ozonium anamorphic state.
There are many coprophilous species, the
most studied being C. cinereus (earlier erroneously
named C. lagopus) on cattle and horse manure
heaps and manured straw (Fig. 19.14d). This
species grows and fruits well in the laboratory
and has been the subject of much research,
ably reviewed by Kües (2000), on the genetics
of mating systems (Pukkila & Casselton, 1991;
Casselton & Riquelme, 2004), cytology (Raju & Lu,
1970; L. Li et al., 1999), morphogenesis (Moore,
1998), gravitropism (Moore et al., 1996), stipe
elongation (Kamada, 1994), nuclear migration,
clamp formation, physiology of fruiting and
other phenomena. Whilst most Coprinus species
are saprotrophic, C. psychromorbidus (¼ ‘diseased
by cold’) belongs to a group of low-temperature
basidiomycetes which are plant pathogens. It is
the cause of snow mould disease of grasses and
other plants in Canada and also causes a postharvest
rot of apples in cold store. It can
continue to grow actively under snow cover
because it possesses special thermal hysteresis
proteins with antifreeze properties (Sholberg &
Gaudet, 1992; Hoshino et al., 2003).
Basidiocarps of Coprinus have thin inaequihymenial
gills with prominent pleurocystidia
and cystesia (see p. 525). Basidiocarps range in
size from a few millimetres in coprophilous
forms to over 30 cm (C. comatus). Spore development
and discharge occurs first at the base of the
gill, followed by autodigestion of the discharged
basidia and the hyphae which supported them.
Chitinase and other hydrolytic enzymes play a
major role in autodigestion (Iten & Matile, 1970;
Miyake et al., 1980). The digested tissue drips
away from the base of the gills as a black fluid
which can be used as writing ink. Meanwhile an
upward wave of basidiospore discharge
continues above the digested tissues. In certain
species, the gills do not deliquesce, or do so only
partially. In C. curtus some limited autodigestion
occurs at the edge of the gill and the gills open,
as in C. plicatilis, by a V-shaped groove which
widens from above (Buller, 1909, 1931). Buller
(1924) has shown that in many species of Coprinus
the basidia are dimorphic, with long and short
forms present in the same gill. The short forms
are fully functional, i.e. the basidia ripen at
different levels of the hymenium. This arrangement
makes it possible to crowd a larger number
of basidia into a given area without interference
in spore release. Trimorphic and tetramorphic
basidia are present in some species.
Sclerotia in Coprinus
Sclerotia are formed by several species. Coprinus
sterquilinus develops its sclerotia at the surface
of cattle dung and, under suitable conditions,
basidiocarps develop from them (Buller, 1924).