R-L categories correct, but text here does not match final assessment. Updated version will be published in IUCN´s Red List June or Nov 2019.
Montagnea arenaria (DC.) Zeller, Montagnites radiosus (Pall.)Henn., Montagnites candollei Fr.
The species is known from Europe, Asia, North and South Africa, North, Central and South America, and in Oceania. In Europe, it occurs mainly in the lowlands, seldom also in lower mountain regions (Spain); it is present mainly in the Mediterranean as well as steppic regions (both open and woody), very rare in Central Europe and absent from arctic, boreal, Atlantic zones and higher mountains.
The species is widespread across the grassy and dry habitats in tropics up to warm regions of the temperate zone throughout the globe and especially frequent in western, central and southern North America, in Spain (Europe) and in Australia. It is probably common also in Africa, Middle-East and Asia, although these areas are not sufficiently studied. In Europe, outside Spain, it is rather occasional or very rare and scattered and in these areas it may be threatened by the habitat degradation and loss.
Red-listed in Armenia, Austria, Czech Republic, Germany, Hungary, Malta, Poland, Slovakia and Spain, and in one region of Russia (Rostov).
The species is a thermophilic, psammophilic, terricolous saprotrophic fungus inhabiting dead plant debris (e.g., rhizomes and roots of Poaceae) in dry and warm grassy habitats (Fraiture and Otto 2015). It grows mostly in dry, open, sandy places, in dunes, deserts, semi-deserts, savannah and steppes, from the tropics up to warm regions of the temperate zone, where it is a relatively frequent fungus (Kreisel 2001, Stasińska and Preis 2002).
In Europe, it typically inhabits dry and sandy sites, like steppes (Austria, Ukraine) and steppe meadows (Ukraine), steppe-like vegetation with Stipa on slopes with southern exposure (Germany, Poland), xerothermic pastures and shrublands (Poland, Slovakia), coastal (Malta, Spain) and inland dunes (Hungary, Slovakia). Rarely, it was found in anthropogenic habitats as Robinia plantation (Poland), recultivated fly-ash area (Czech Republic) and roadsides (Ukraine). It requires mainly sandy, neutral to slightly basic dry soil, with rather low to moderate nitrogen content. It may also occur on brown soil, black earth and loess. Its basidiomata are known to appear after heavy rainfalls.
The sites where this species occurs are threatened mainly by intensification or cessation of grassland management, eutrophication and afforestation.
There is a need for site monitoring and protection (active if vegetation succession should be prevented) in the areas where the species is rare. In such cases, legal species protection may be considered. Continuous monitoring of the species distribution in Europe and globally is recommended.
The research on M. radiosa distribution is needed as well as on its ecology, habitat requirements and mode of fruiting. Special attention should be paid to the factors limiting the species occurrence near its distribution ends.
Fraiture A., Otto P. (eds.) 2015. Distribution, ecology and status of 51 macromycetes in Europe. Results of the ECCF Mapping Programme. Botanic Garden Meise, Belgium.
Kreisel H. 2001. Checklist of the gasteral and secotioid Basidiomycetes of Europe, Africa and the Middle-East. Osterr. Z. Pilzk., N.S. 10: 213–313.
Stasińska M., Prajs B. 2002. New record of Montagnea arenaria (Fungi, Agaricales) and its distribution in Poland. Polish Botanical Journal 47(2): 211–213.