Agaricales of the dunes of Galicia (IV): Marasmiellus ciesanus (Omphalotaceae), a new species found in the National Maritime-Terrestrial Park of the Atlantic Islands of Galicia (Spain)

Marasmiellus ciesanus, collected in open dunes in the National Maritime-Terrestrial Park of the Atlantic Islands of Galicia, is illustrated and described as a new species from Spain on the basis of morphological features. This species is close to other taxa of the subsection Quercini, in which it occupies an isolated position due to its unusual small spores broadly ellipsoid to oblong-lacrimoid, versiform cheilo- and caulocystidia and specific substrata (dead stalks of Helichrysum picardii var. virescens).