are many additional ecological roles in Agari-
cales, including plant pathogens (e.g.,Moni-
liophthora/Crinipellis) (Meinhardt et al. 2008 ),
mycoparasites (e.g., Squamanita) (Matheny
and Griffith 2010 ), basidiolichens (e.g.,Liche-
nomphaliaandDictyonema) (Dal-Forno et al.
2013 ; Lawrey et al. 2009 ), attine ant cultivars
(Leucoagaricus/Leucocoprinus clade) (Mueller
et al. 2005 ), or termite cultivars (Termitomyces)
(Aanen et al. 2002 ). The ecology of many Agar-
icales species remains poorly understood, and
new insights from molecular and isotopic data
are challenging long-standing views even in
relatively well-studied groups. For example,
the so-called waxcaps (Hygrocybesensu lato)
have historically been considered saprotrophs
but now are thought to be involved in some
kind of biotrophic association (Lodge et al.
2013 ; Seitzman et al. 2011 ).
Systematics: three landmark papers pub-
lished in recent years have redefined the taxo-
nomic organization of Agaricales species and
their closest relatives: (1) Moncalvo et al. ( 2002 )
presented the first broad phylogeny of the
order, based on nuc-lsu rRNA, which resolved
117 clades and outlined conflicts with tradi-
tional morphologically defined groups; (2)
Matheny et al. ( 2006 ) presented the first major
multilocus overview of the order, including the
protein-coding genes rpb1, rpb2, and tef1-
alpha, and defined six major infraordinal
clades: agaricoid, tricholomatoid, marasmioid,
hygrophoroid, pluteoid, and plicaturopsidoid
clades, although support for some of these
groupings was weak; (3) Binder et al. ( 2010 )
built on the data set of Matheny et al. ( 2006 )
and formally recognized the plicaturopsidoid
clade as the order Amylocorticiales.
Recent monographs on Agaricales include
the titles of the Fungi Europaei series on
Agaricus(Parra-Sa ́nchez 2008 ),Amanita(Neville
and Poumarat 2004 ), Conocybe-Pholiotina
(Hausknecht 2009 ), and the family Stropharia-
ceae (Noordeloos 2011 ). Outside Europe mono-
graphic work at the continental scale is rare, a
situation that may change with large-scale cata-
loging efforts that include the use of molecular
data, such as the North American Mycoflora
project (Bruns 2012 ). Modern global mono-
graphs are lacking for all major genera of Agar-
icales.Agaricoid clade: this clade is well supported in the study
of Matheny et al. ( 2006 ) and is dominated by gilled
pileate-stipitate forms with pigmented spores (brown,
purple-brown, black). Exceptions to this general pattern
include (1) white-spored taxa in Agaricaceae (Lepiota
and allied genera), Cystodermateae, and Hydnangiaceae
(e.g.,Laccaria); (2) secotioid and gasteroid taxa that
have repeatedly evolved in different lineages (e.g., Agar-
icaceae,Cortinarius); and (3) cyphelloid forms in the
generaPellidiscusandPhaeosolenia(Bodensteiner et al.
2004 ). At least six ECM lineages are included in this
clade: Cortinarius, Descolea (and allied sequestrate
taxa), Inocybaceae, Laccaria(and allied sequestrate
taxa),Phaeocollybia, and some groups of Hymenogas-
traceae (Alnicola,Hebeloma). Most other members of
the agaricoid clade are saprotrophs associated with the
litter layer and similar substrates (e.g.,Agaricus,Copri-
nopsis) or wood decayers (e.g.,Hypholoma). Taxa with
recent phylogenetic studies include Agaricaceae
(Vellinga 2004 ; Vellinga et al. 2011 ), Bolbitiaceae (To ́th
et al. 2013 ), Cortinariaceae (Frøslev et al. 2005 ;Garnica
et al. 2005 ;Peintneretal. 2004 ), Crepidotaceae (Aime
et al. 2005 ), Cystodermateae (Saar et al. 2009 ), Gymno-
pileae (Guzma ́n-Da ́valos et al. 2003 ), Hebelomateae
(Boyle et al. 2006 ;Moreauetal. 2006 ), Inocybaceae
(Matheny 2005 ;Rybergetal. 2010 ), Nidulariaceae
(Zhao et al. 2007 ), Psathyrellaceae (Nagy et al. 2012 ),
Strophariaceae (Ramı ́rez-Cruz et al. 2013 ), Tubarieae
(Gulden et al. 2005 ), and several secotioid/gasteroid
taxa usually nested within agaricoid relatives (Larsson
and Jeppson 2008 ; Lebel and Syme 2012 ).
Tricholomatoid clade: pileate-stipitate gilled mush-
rooms with white or pink spores dominate this lineage,
which includes four traditionally recognized families:
Entolomataceae, Lyophyllaceae, Mycenaceae, and a
restricted version of Tricholomataceae. A fifth lineage
includes the ECMCatathelasmaand the saprotrophic
Callistosporium. Additional ECM origins have also
occurred inEntoloma,Lyophyllum,andTricholomata-
ceae. The clade also includes soil/litter saprotrophs (e.g.,
Clitocybe), mycoparasites (e.g., Asterophora), wood
decayers associated with white rot (e.g.,Mycena)or
brown rot (e.g.,Ossicaulis), and termite cultivars (Termi-
tomyces). Entolomataceae remains one of the most dis-
tinct groups in Agaricales because of the pinkish spores
that are warted, ridged, or angular. Co-David et al. ( 2009 )
recognize two broadly defined genera in the family (Ento-
lomaandClitopilus), while other authors prefer to recog-
nize several narrowly defined genera (Baroni and
Matheny 2011 ; Largent et al. 2011 ). The Lyophyllaceae
has also been reviewed using molecular phylogenies
(Hofstetter et al. 2002 ).Thetaxonomyofmanytradition-
ally recognized genera (e.g., Tricholoma, Clitocybe,
Lepista,Mycena) is still in flux.
Marasmioid clade: this lineage is dominated by
white-spored saprotrophic species associated with410 D.S. Hibbett et al.