Fungalpedia – Note 3069, Marasmiellomycena
Marasmiellomycena De la Peña-Lastra, Mateos, Kolařík, Ševčíková & Antonín.
Citation when using this data: Senanayake IC et al. 2023 – Fungalpedia.
Index Fungorum, Faceoffungi, MycoBank, GenBank, Fig 1.
Classification: Porotheleaceae, Agaricales, Agaricomycetidae, Agaricomycetes, Agaricomycotina, Basidiomycota, Fungi.
Diagnosis: This genus differs from other genera by mycenoid habit, sinuate, adnexed to adnate lamellae, presence of pileocystidia differs by basidiomata turning brownish on handling, a distinctly squamulose pileus, clitocyboid basidiomata, a floccose or floccose-fibrillose white stipe, pileipellis in the form of a regular cutis and constantly cylindrical caulocystidia and weakly amyloid, globose to broadly ellipsoid basidiospores.
Saprobic on dead wood. Basidiomata omphaloid or marasmioid, non-fragile. Pileus thin-fleshed, minutely tomentose, pubescent, granulose to subsquamulose. Lamellae well-developed, frequently forked, anastomose, adnate, sub-decurrent or decurrent, triangular or arcuate. Stipe central, filiform, entirely pruinose or pruinose-floccose, flesh thin. Basal tomentum present. Spores smooth, inamyloid. Basidia mostly tetrasporic. Cheilocystidia less distinct. Pleurocystidia absent. Pileipellis a cutis or with transitions to a trichoderm, terminal elements cylindrical, fusiform, lageniform or mucronate with or without excrescences or long rostrum (pileocystidioid structures). Clamp connections present. Chemical reactions metachromatic in cresyl blue or not, no other part of basidiomata dextrinoid or amyloid. Ecology saprotrophic, on dead wood and decaying leaves.
Notes: Our three new collections (BRNM 552658, BRNM 552721, BRNM 552654) are morphologically identical and they shares many similar characters with Porotheleum omphaliiforme. Therefore, this well-supported clade herein introduce as Marasmiellomycena gen. nov. Vu et al. (2018) predicted that optimal thresholds for fungi (at least for filamentous) at the genus level of 98.2% based on LSU barcodes and 94.3% based on ITS barcodes. The genetic similarity of the genus Marasmiellomycena to neighboring genera, expressed by the similarity of M. pseudoomphaliiformis (type collection) to P. parvulum and (sequences identified as) P. fimbriatum, is 97.8% for LSU, and 88.9% for ITS. Marasmiellomycena has morphological affinities with Marasmiellus, Hemimycena, Pulverulina, and several mycenoid genera in Mycenaceae (Redhead and Singer 1981; Moncalvo et al. 2002; Matheny et al. 2006; Redhead 2012; Matheny et al. 2020).
The phylogenetically closely related genus, Pseudohydropus Vizzini & Consiglio differs from Marasmiellomycena by a mycenoid habit, sinuate, adnexed to adnate lamellae, globose to broadly ellipsoid basidiospores and the presence of pileocystidia (Consiglio et al. 2021). Vizzinia (see below) differs by basidiomata turning brown on handling, a distinctly squamulose pileus, a floccose or floccose-fibrillose stipe, weakly amyloid spores, and the absence of cheilocystidia (Consiglio et al. 2021). Pulverulina ulmicola (H.E. Bigelow) Matheny & K.W. Hughes, the only species of the genus Pulverulina Matheny & K.W. Hughes, differs by clitocyboid basidiomata, white stipe, pileipellis in the form of a regular cutis and constantly cylindrical caulocystidia (Matheny et al. 2020).
Type species: Marasmiellomycena pseudoomphaliiformis Antonín & Ševčíková.
Other accepted species: Species Fungorum – search Marasmiellomycena.
EPSON scanner image
Figure 1 – Marasmiellomycena pseudoomphaliiformis (BRNM 552721). a Basidiomata. b Cheilocystidia. c Basidia. d Stipitipellis with caulocystidia. e Basidiospores. f Pileipellis with pileocystidia. Scale bar = 10 μm.
References
Redhead SA, Singer R. 1981 – Resinomycena gen. nov. (Agaricales), an ally of Hydropus, Mycena and Baeospora. Mycotaxon 13: 150–170.
Redhead SA. 2012 – Nomenclatural novelties. Index Fungorum 14: 1.
Entry by
Indunil C. Senanayake, Innovative Institute for Plant Health/ Key Laboratory of Green Prevention and Control on Fruits and Vegetables in South China, Ministry of Agriculture and Rural Affairs, Zhongkai University of Agriculture and Engineering, Haizhu District, Guangzhou 510225, Guangdong, China., Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand., Guangdong Provincial Key Laboratory for Plant Epigenetics, College of Life Science and Oceanography, Shenzhen University, 3688, Nanhai Avenue, Nanshan, Shenzhen, Guangdong 518055, China., University of L’Aquila, Department MeSVA, sect. Environmental Sciences, Via Vetoio, 67100 Coppito (AQ), Italy.
Published online 31 August 2026