Arrhenia

Arrhenia is a genus of fungi in the family Hygrophoraceae. Arrhenia also includes species formerly placed in the genera Leptoglossum and Phaeotellus and the lectotype species itself has an unusual growth form that would not normally be called agaricoid. All of the species grow in association with photosynthetic cryptogams such as mosses, including peat moss, and alga scums on decaying wood, and soil crusts consisting of mixes of such organisms. Typically the fruitbodies of Arrhenia species are grey to black or blackish brown, being pigmented by incrusting melanized pigments on the hyphae.

Taxonomy
Arrhenia was named for the Swedish botanist Johan Peter Arrhenius.

Species
, the following species are recognised in the genus Arrhenia:
 * Arrhenia acerosa (Fr.) Kühner
 * Arrhenia alnetora (Singer) Redhead
 * Arrhenia andina (Corner) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia antarctica (Singer) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia auriscalpium (Fr.) Fr.
 * Arrhenia australis (Cleland) Grgur.
 * Arrhenia baeospora (Singer) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia bigelowii Voitk, Lickey & I. Saar
 * Arrhenia chilensis (Mont.) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia chlorocyanea (Pat.) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia cupuliformis Henn.
 * Arrhenia cyathella (J. Favre & Schweers ex Kuyper) Elborne
 * Arrhenia cystidiata Desjardin & B.A. Perry
 * Arrhenia discorosea (Pilát) Zvyagina, A.V. Alexandrova & Bulyonk.
 * Arrhenia eburnea Barrasa & V.J. Rico
 * Arrhenia elegans (Pers.) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia epichysium (Pers.) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia favrei (Watling) P.-A. Moreau & Courtec.
 * Arrhenia fenicola C.R.J. Hay & Thorn
 * Arrhenia fissa (Leyss.) Redhead
 * Arrhenia fusconigra (P.D. Orton) P.-A. Moreau & Courtec.
 * Arrhenia gerardiana (Peck) Elborne
 * Arrhenia glauca (Batsch) Bon & Courtec.
 * Arrhenia griseopallida (Desm.) Watling
 * Arrhenia hohensis (A.H. Sm.) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia juncorum P.-A. Moreau & Corriol
 * Arrhenia kuehneri Blanco-Dios
 * Arrhenia latispora (J. Favre) Bon & Courtec.
 * Arrhenia leucotricha P.-A. Moreau & Corriol
 * Arrhenia lilacinicolor (Bon) P.-A. Moreau & Courtec.
 * Arrhenia lobata (Pers.) Kühner & Lamoure ex Redhead
 * Arrhenia lundellii (Pilát) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia luteopallida (Kuyper & Hauskn.) Barrasa & V.J. Rico
 * Arrhenia monsducalis Albanese, Battistin, Berna, Boragine, Ercole & Vizzini
 * Arrhenia obatra (J. Favre) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia obscurata (D.A. Reid) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia omnivora (Agerer) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia parvivelutina (Clémençon & Irlet) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia pauxilla (Clémençon) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia peltigerina (Peck) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia philonotis (Lasch) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia polycephala (Bres.) E. Ludw.
 * Arrhenia pontevedrana Blanco-Dios
 * Arrhenia pubescentipes (H.E. Bigelow) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia rainierensis (H.E. Bigelow) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia retiruga (Bull.) Redhead
 * Arrhenia rickenii (Hora) Watling
 * Arrhenia rigidipes (Lamoure) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia rustica (Fr.) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia salina (Høil.) Bon & Courtec.
 * Arrhenia spathulata (Fr.) Redhead
 * Arrhenia sphaerospora (Lamoure) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia stercoraria (Barrasa, Esteve-Rav. & Sánchez Nieto) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia subandina (Singer) P.M. Kirk & Redhead
 * Arrhenia subglobisemen Corriol
 * Arrhenia subglobispora (G. Moreno, Heykoop & E. Horak) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia subobscura (Singer) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia svalbardensis Gulden, I. Saar & Lücking
 * Arrhenia tabaresiana (Vila & Llimona) Vila
 * Arrhenia telmatiaea (Berk. & Cooke) Voitk & I. Saar
 * Arrhenia tillii (Krisai & Noordel.) Krisai & I. Saar
 * Arrhenia trigonospora (Lamoure) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia umbratilis (Fr.) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia velutipes (P.D. Orton) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia violaceoviridis (Courtec.) Courtec.
 * Arrhenia viridimammata (Pilát) Redhead, Lutzoni, Moncalvo & Vilgalys
 * Arrhenia volkertii (Murrill) Redhead, Lutzoni, Moncalvo & Vilgalys