IBONE   05434
INSTITUTO DE BOTANICA DEL NORDESTE
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Study on tropical and subtropical Marasmius: Four new species of the sect. Spinulosi.
Autor/es:
RAMIREZ NATALIA; ANTONÍN, VLADIMÍR; NIVEIRO, NICOLÁS; ALBERTÓ, EDGARDO; MICHLIG, ANDREA
Lugar:
San Juan
Reunión:
Congreso; 11 Internationa Mycological Congress; 2018
Institución organizadora:
Internationa Mycological Congress
Resumen:
Marasmius is a large genus with worldwide distribution with more than 500 species, which are characterized by their generally small to medium-sized basidiomata, often membranaceous pileus, and for the ability to be revivescent when are rehydrated. This last feature makes them tolerate conditions of seasonal drought or high temperatures, what allows them to be diverse and abundant in tropical and subtropical forests. Marasmius comprises many sections and subsections (e.g. Globulares, Marasmius, Neosessiles, Sicci,). However, recently studies tested the monophyly of the sections traditionally proposed by Singer and confirm that they are highly homoplasic. A small group of species of Marasmius, characterized by having setae in the pileus and stipe surface, and even in the hymenophore (e.g. M. actinopus, M. jalapensis, M. coharens), belong to section Spinulosi. The species of Marasmius with setae are not common, being better known from southeastern Asia and Neotropical region. The aim of this study is to propose four new species and to present a worldwide key of Marasmius sect. Spinulosi. We studied specimens identified as M. jalapensis, M. spiculosus, M. echinulatus, and M. flammans deposited in CTES, K, LIL, NY and XAL mycological collections, including type specimens. For microscopic characters, a light microscopy (LM) and a scanning electron microscopy (SEM) were used. We discovered two species never described before from northern Argentina and we segregated other two species from the M. jalapensis concept based on type material analyses. Marasmius sp. 1, resembling M. chrysoblepharis, is characterized by its yellowish-orange pileus, with a sulcate-striate margin, entirely pilose orange-brown stipe, setiform caulocystidia with a tapering and thick-walled apex and bacilliform to fusiform large spores. Marasmius sp. 2 has characters between M. trichotus and M. ciliatus, but differs in its large setiform cystidia on the pileus and stipe surface, the absence of broom cells in the stipitipellis and spores size. Both species are collected in northern Argentina. Marasmius sp. 3 and Marasmius sp. 4 are segregated from the M. jalapensis concept. Marasmius sp. 3 differs by its narrower spores and two cheilocystidia types and it is distributed in the tropical and subtropical regions of South America. Marasmius sp. 4 is restricted to northern Africa and differs mainly by its smaller spores. Marasmius jalapensis is confined to the mesophilic mountain forests in Mexico. A key of the tropical and subtropical species of Marasmius sect. Spinulosi is presented. In conclusion, based on the morphological, biogeographic and phylogenetic characteristics, we propose these four species as new for science.