Laccaria fraterna ( Cooke & Mass . : Sacc . ) Pegler , 1965 ( Agaricales , Basidiomycota ) associated with exotic Eucalyptus sp . in northern Argentina and Paraguay

Laccaria fraterna is recorded for the first time from the Cordillera Department, Paraguay and from northern Argentina. Both macroscopic and microscopic morphological characteristics of the basidiomata are described. Photographs of fresh material are presented along with photographs of the microscopic characters. Comments regarding the distribution and taxonomy are provided.


Introduction
Laccaria Berk.and Broome is a cosmopolitan fungal genus of ecological importance due to its ectomycorrhizal associations with a wide range of conifers and angiosperms and is especially important in Eucalyptus plantations around the world (Kropp andMueller 1999, Wilson et al. 2013).Formerly, this genus was placed within the families Hydnangiaceae (Kühner 1980), Laccariaceae (Jülich 1981) and Tricholomataceae (Singer 1986), respectively.In the early 1980s, Kühner (1980) included Laccaria in the family Hydnangiaceae within Agaricales, which contains agaricoid fungi along with mycorrhizal gasteroid species.The genera Laccaria, Hydnangium and Podohydnangium are similar in morphological characters.They all possess basidiospores with an echinulate ornamentation, which suggests a close phylogenetic relationship between them (Kropp and Mueller 1999).
Laccaria is characterized by its glabrous, radially striate and hygrophanous pileus, with a color variation ranging from brown-ferruginous, reddish brown to brown-violet.The lamellae are broad and thick, with regular hymenophoral trama.The spores are globose to amygdaliform, ornamented with warts or spines.The basidia have 2 to 4 sterigmata and lack cystidia (McNabb 1972, Tommerup et al. 1991).
Laccaria has a cosmopolitan distribution, and is distributed mainly in temperate and tropical regions (Kropp and Mueller 1999).The genus contains 75 species (Kirk et al. 2008), having been well studied in Asia, Oceania, Europe and America (McNabb 1972, Castro Cerceda and Freire 1984, Mueller and Vellinga 1986, Tommerup et NOTES ON GEOGRAPHIC DISTRIBUTION al. 1991, Kropp and Mueller 1999, Wilson et al. 2013).In South America, 9 Laccaria species are recorded from Argentina (Niveiro and Albertó 2013) and 10 species are recorded from Brazil, with most records occurring within the southern states of Brazil (Giachini et al. 2004, Capelari et al. 2015).Here we report the first record of the genus Laccaria within Paraguay.In this paper, we describe and illustrate Laccaria fraterna based on recent collections made in northern Argentina and Paraguay.

Methods
The samples studied in this paper were collected in the city of Piribebuy-Pirareta, Cordillera Department, Paraguay and Cerro San Javier, Tucumán Province, Argentina,.Macroscopic data, including size, color and consistency, were described from fresh material.For structural microscopic study of dried material, rehydrated preparations were analyzed with KOH (5%) and stained with Phloxine (1%) and Congo Red (1%).For the analysis of microchemical reactions Melzer's reagent was used (Wright and Albertó 2002).Samples were observed through an optical microscope Carl Zeiss with 40× and 100× objectives with immersion oil and all the measurement were made with the oil immersion objective.The examined material was deposited at the Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Asunción Herbarium (FACEN) and at the Instituto de Botánica del Nordeste Herbarium (CTES).
Pileus 15-55 mm in diameter, ovate to hemispheric when young, then campanulate and finally plano-convex at maturity, somewhat depressed in the center with a small umbo at the disc, reddish brown towards the center, reddish orange, orange to yellow at the margin, surface dry with striations, and sometimes sulcate margin.Lamellae pinkish to coral pink, moderately distant, adnate with a decurrent tooth, margin even, 1-3 mm wide, with 2 to 6 lengths lamellulae.Stipe 30-70 × 2-5 mm, equal or slightly thickening towards the apex, central, cylindrical, hollow, reddish brown, fibrous, with small white floccules at the junction with the pileus.Context thin, fleshy, reddish orange.Taste and odor fungoid.Spore print white.

Figure 5 .
Figure 5. Distribution map of Laccaria fraterna in subtropical South America.