Opuscula Philolichenum, 16: 188–266. 2017. *pdf effectively published online 28April2017 via (http://sweetgum.nybg.org/science/op/) A revision of lichenicolous fungi growing on Cladonia, mainly from the Northern Hemisphere, with a worldwide key to the known species MIKHAIL P. ZHURBENKO 1 AND RAQUEL PINO-BODAS 2 ABSTRACT. – The paper documents 70 species of fungi found on species of the lichen genus Cladonia, 65 of which are obligately lichenicolous. One genus, Brackelia, and seven species, Biciliopsis cladoniae, Brackelia lunkei, Caeruleoconidia biazrovii, Neolamya ahtii, Niesslia keissleri, Sclerococcum crassitunicatum and S. epicladonia, are here described as new to science. The names Caeruleoconidia and C. ochrolechiae are validated. Ameroconium cladoniae is considered as a heterotypic synonym of Taeniolella beschiana. Merismatium cladoniicola most likely is a heterotypic synonym of M. decolorans. Taxonomic notes on critical specimens, including those of Abrothallus cf. pezizicola, Arthonia cf. lepidophila, Cladophialophora cf. cladoniae, Hainesia cf. bryonorae, Merismatium cf. nigritellum as well as of unidentified species of Acremonium, Dactylospora, Leptosphaeria, Lichenopeltella and Pronectria found on Cladonia are provided. Cercidospora cladoniicola, Didymocyrtis cladoniicola, Hainesia longicladoniae, Pezizella ucrainica, Plectocarpon cladoniae and Polycoccum laursenii are documented as new to Asia. Biazrovia stereocaulicola, Hainesia longicladoniae and Polycoccum microcarpum are new to North America. The following species are new to various countries: Argentina (Bachmanniomyces uncialicola and Niesslia cladoniicola), Finland (Didymocyrtis foliaceiphila and Roselliniella cladoniae), Japan (Lichenosticta alcicorniaria), Lithuania (Abrothallus cf. pezizicola), Mongolia (Arthonia digitatae, Didymocyrtis cladoniicola, Epicladonia stenospora s. lat., Lichenostigma alpinum s. lat., Phaeopyxis punctum, Sphaerellothecium cladoniicola and Taeniolella beschiana), New Zealand (Abrothallus cladoniae s. lat. and Epicladonia sandstedei), Norway (Arthonia digitatae), Kazakhstan (Sphaerellothecium cladoniae), Kyrgyzstan (Epicladonia sandstedei), Papua New Guinea (Opegrapha cladoniicola), Portugal (Epicladonia stenospora s. lat.), Russia (Abrothallus cladoniae s. lat., A. cf. pezizicola, Arthrorhaphis aeruginosa, Didymocyrtis foliaceiphila, Hainesia longicladoniae, Neoburgoa freyi, Pezizella ucrainica and Polycoccum laursenii), Spain (Lichenoconium aeruginosum), U.S.A. (Biazrovia stereocaulicola, Hainesia longicladoniae, Niesslia cladoniicola and Polycoccum microcarpum), Venezuela (Roselliniella cladoniae) and Vietnam (Pyrenidium actinellum s. lat.). Epicladonia sandstedei and E. stenospora s. lat. are new to Macaronesia. Heterocephalacria bachmannii is for the first time documented in the polar desert biome. Biazrovia stereocaulicola, Coniochaeta sp., Merismatium coccisporum and Pyrenidium actinellum s. lat. are newly reported to occur on Cladonia. A key to 138 species of fungi so far known to occur on Cladonia is provided. KEYWORDS. – Cladoniicolous fungi, new taxa, new records, new host lichens, taxonomy. INTRODUCTION Cladonia (Cladoniaceae) is a subcosmopolitan genus of macrolichens characterized by a dimorphic thallus, formed by a crustose or squamulose primary thallus that is sometimes evanescent, and fruticose podetia (Ahti & Stenroos 2013). It currently comprises 470 species (T. Ahti, pers. comm., 2016) 1MIKHAIL P. ZHURBENKO – Lab. of the Systematics and Geography of Fungi, Komarov Botanical Institute Russian Academy of Sciences, Professor Popov 2, St. Petersburg, 197376, Russia. – e–mail: [email protected] 2RAQUEL PINO-BODAS – Real Jardín Botánico de Madrid (CSIC), Plaza Murillo 2, E-28014 Madrid, Spain. – e–mail: [email protected] 188 and, along with Arthonia, Lecanora, Pertusaria and Xanthoparmelia, belongs to the five largest lichen genera in terms of species numbers (Lücking et al. 2016). The species of Cladonia mostly grow on soil, but also occur on tree bases and decaying wood, and play an important role in the ground vegetation of tundra and boreal forest vegetation biomes (Ahti & Oksanen 1990). They also frequently occur in many temperate and even tropical habitats (Ahti 2000). Zhurbenko and Alstrup (2004) provided a key to 77 species of lichenicolous fungi that occurred on Cladonia. Subsequently, 25 further species of fungi have been reported from this host lichen genus, viz. Ameroconium cladoniae U. Braun & Zhurb. (Zhurbenko & Braun 2013), Arthonia coniocraeae Brackel (Brackel 2010b), A. coronata Etayo (Coppins & Aptroot 2009), A. rangiformicola Brackel & Etayo (Brackel 2015), Calongeomyces gibelluloides (D. Hawksw. & Etayo) D. Hawksw. & Etayo (Hawksworth & Etayo 2010), Cladophialophora cladoniae (Diederich) Diederich (Diederich 2010), Dacampia cladoniicola Halici & A.O. Türk (Halici et al. 2008), Didymocyrtis cladoniicola (Diederich, Kocourk. & Etayo) Ertz & Diederich, D. foliaceiphila (Diederich, Kocourk. & Etayo) Ertz & Diederich (both Diederich et al. 2007), Endophragmiella stordeuriana U. Braun, Zhurb., Diederich, Tsurykau & Heuchert (Zhurbenko et al. 2015b), Galloea cladoniicola Alstrup & Søchting (Alstrup & Søchting 2009), Hainesia brevicladoniae Diederich & Van den Boom, H. longicladoniae Diederich & Van den Boom (both Diederich & Van den Boom 2013), Lichenoconium aeruginosum Diederich, M. Brand, Van den Boom & Lawrey (Lawrey et al. 2011), Lichenopeltella rangiferinae Brackel (Brackel 2011), L. uncialicola Brackel (Brackel 2010a), Micarea kemmleri Brackel (Brackel 2016), Nectriopsis cariosae Brackel & D.G. Zimmermann (Brackel & Zimmermann 2012), Neoburgoa freyi Diederich, Zimmermann & Lawrey (Lawrey et al. 2016), Phoma grumantiana Zhurb. & Diederich (Diederich et al. 2007), Pronectria minuta Motiej. & Kukwa (Motiejūnaitė & Kukwa 2008), Ramichloridium cladoniicola U. Braun & Heuchert (Braun et al. 2009), Stigmidium cladoniicola Zhurb. & Diederich (Zhurbenko & Diederich 2008), S. subcladoniicola Van den Boom (Van den Boom 2016) and Syspastospora cladoniae Etayo (Etayo 2008). The aims of the paper are to 1) provide new information on the taxonomy, geographic distribution and host preferences of fungi that occur on Cladonia; 2) describe a new genus and seven new species of cladoniicolous fungi; and 3) present an updated worlwide key to the species of lichenicolous fungi that occur on Cladonia. MATERIALS AND METHODS The study is based on 747 examined specimens of fungi (including some lichenized ones) growing on Cladonia housed in the herbaria LE (667 specimens) and H (80 specimens), with two duplicates in herb. Diederich. Of these 727 were collected in the Northern Hemisphere (including 389 specimens collected by M. P. Zhurbenko and 26 by R. Pino-Bodas) and 21 were from the Southern Hemisphere. Within the Northern Hemisphere, 622 specimens were from the arctic and boreal forest (taiga) biomes, and 105 represented more southern biomes. The material was examined and photographed using a Stemi 2000−CS dissecting microscope and Axio Imager A1 compound microscope equipped with Nomarski differential interference contrast optics. Microscopic examination was carried out in water, 10% KOH (K), Lugol’s iodine, directly (I) or after 10% KOH pre-treatment (K/I), Brilliant Cresyl blue (BCr), lactic acid, nitric acid (N), Phloxine B or Phloxine B after 10% KOH pre-treatment. Measurements were taken from water mounts, unless otherwise indicated. When ten or more measurements are summarized in the text, they are indicated as (minimum–){X −SD}−{X +SD}(–maximum), where X is the arithmetic mean and SD the corresponding standard deviation, followed by the number of measurements. The length/breadth ratios of ascospores and conidia are indicated as l/b and given in the same way. The DNA of Coniochaeta sp. was extracted using E.Z.N.A.® Forensic DNA Kit (OMEGA) according to the manufacturer’s instructions. The ITS rDNA region was amplified with the primers ITS1F (Gardes and Bruns 1993) and ITS4 (White et al. 1990). The PCR was done with Ready-to-Go-PCR Beads (GE Healthcare Life Sciences, Little Chalfont, UK), using 3 μl of DNA extracted. The PCR program was described in Pino-Bodas et al. (2013). The PCR product was purified with Illustra GFX PCR DNA and Gel Band Purification Kit (GE Healthcare) and the sequencing was performed at Macrogen Europe (www.macrogen.com). A BLASTn search (Altschul et al. 1997) was used to compare the ITS rDNA sequence with the sequences in the GenBank. 189 CATALOGUE OF THE STUDIED TAXA Some lichenized or not truly lichenicolous fungi occurring on Cladonia are also included here even though they are not obligately lichenicolous. The cited specimens are organized geographically, first for the Northern Hemisphere (starting with Europe), then for the Southern Hemisphere. Descriptions and occasional taxonomic observations are provided for the insufficiently known or critical taxa or for the deviating or insufficiently known characters of the well-known species. Abrothallus cladoniae R. Sant. & D. Hawksw. s. lat. DESCRIPTION. – Apothecia convex and often somewhat applanate above, sessile, constricted at the base, stipe not observed, 125‒375 µm in diameter, black, matt, distinct pruina not seen. Epihymenium medium to dark greenish to olive, sometimes with yellow orange crystals (in Stenroos 5782a) or indistinct (in LE 308478). Hymenium 30‒40 µm tall (including epihymenium), light to medium greenish olive brown, sometimes with purple stripes (in Stenroos 5782a) or medium purplish brown (in LE 308478), K+ intensively