Proposed Operational Classification Of Laccaria
	The classification used in this monograph is based on an attempt to rigorously analyze all available data using cladistic methods. The employed data set included data on macro- and micromorphology of basidiomata and somatic culture mats, cytology, and basidiospore wall ultrastructure. Two major subgroups within the North American taxa of Laccaria were identified in these analyses (Figures 4 and 5). One group consists of all taxa lacking violet basidioma pigments plus L. oblongospora with the remaining taxa possessing violet basidioma pigments comprising the other subgroup. While these two subgroups are clearly separated on the cladograms, they are not supported by any synapomorphies. No characters, pleisiomorphic nor apomorphic, support the recognition of the taxa comprising the basal group as forming a monophyletic group separate from the rest of the ingroup taxa. Additionally, while the grade consisting of L. trichodermophora through L. vinaceobrunnea appears well supported by the presence of violet mycelium at the stipe base and violet culture mats on PDA and MMN, these character states were also present in the other main subgroup because of L. oblongospora. Taxa need to be based on the occurrence of unique sets of derived characters, and thus, these two subgroups should not be formally recognized. The concept of metataxa was proposed to provide a means to recognize unresolved groups (e.g., Donoghue, 1985, de Queiroz and Donoghue, 1988). Because data do not exist to refute their monophyly, two subgroups are treated as metasections in this monograph, metasections Laccaria and Amethystina. Metasection Amethystina is supported by two character state changes, presence of violet mycelium at stipe base and violet somatic mats on PDA and MMN media. Metasections were used in this treatment, even though metataxa have been criticized by a number of authors (e.g., Kluge, 1989; Nixon and Wheeler, 1990; de Queiroz and Gauthier, 1990), to provide an operational classification and provide a testable hypothesis of relationships within Laccaria. Although taxa in metasection Amethystina are almost fully resolved, only the clade consisting of L. amethysteo-occidentalis, L. amethystina and L. vinaceobrunnea is supported by a synamomorphy, the presence of large, clavate cheilocystidia (Figures 4 and 5). For this reason, metasection Amethystina is not further divided. Similarily, no subgroups are recognized within metasection Laccaria. This classification differs from previously published classifications (Table 3) by the recognition of fewer subgeneric groups. The three classifications presented in Table 3 all recognized a separate group, either section or stirps, for L. trullissata and L. maritima. These two taxa formed a trichotomy with L. ochropurpurea in the cladistic analyses (Figures 4 and 5) and could not be recognized as a separate monophyletic group. The results of these analyses are in conflict with the hypothesis that the Laccaria species characterized by having bisterigmate basidia comprise a monophyletic group separate from tetrasterigmate taxa. Bon's (1983) Stirps Ohiensis and Ballero and Contu's (1989) Subsection Bisporae are paraphyletic, based on my analyses, and therefore, are not recognized. The tree topology shown in Figure 4 and 5 is concordant with the results obtained to date on relationships based on molecular data. Analyses of RFLPs of mtDNA (Gardes et al., 1991a) indicated that L. laccata var. pallidifolia was phenetically more similar to the L. bicolor complex than L. proxima was to the L. bicolor complex. The employed isolates of L. amethystina were phenetically distant based on mtDNA RFLPs from all of these taxa (Gardes et al., 1991a). Similarily, Gardes and colleagues (Gardes et al., 1991b) reported that sequence variation in the internal transcribed spacer (ITS) of the nuclear ribosomal repeat unit was less between the one tested isolate of L. laccata var. pallidifolia and the three tested isolates of L. bicolor sensu lato than between L. proxima and the L. bicolor complex. While these data do not resolve the issue of where to root the network presented in Figure 4, they are concordant with placing L. proxima, L. laccata and taxa in the L. bicolor complex in a linear series.
	These conclusions are summarized below in the Conspectus of North American Taxa.
	Conspectus of North American Taxa
	AGARICALES, TRICHOLOMATACEAE METASECTION Laccaria Laccaria proxima Laccaria oblongospora Laccaria laccata var. laccata Laccaria laccata var. pallidifolia Laccaria longipes Laccaria fraterna Laccaria montana Laccaria pumila Laccaria striatula Laccaria ohiensis Laccaria tortilis METASECTION Amethystina Laccaria trichodermophora Laccaria bicolor Laccaria nobilis Laccaria trullissata Laccaria maritima Laccaria ochropurpurea Laccaria amethysteo-occidentalis Laccaria amethystina Laccaria vinaceobrunnea