Phellinotus Drechsler-Santos, Robledo & Rajchenb., 2016

Drechsler-Santos, Elisandro Ricardo, Robledo, Gerardo Lucio, Lima- Júnior, Nelson C., Malosso, Elaine, Reck, Mateus A., Gibertoni, Tatiana B., De Queiroz Cavalcanti, Maria A. & Rajchenberg, Mario, 2016, Phellinotus, a new neotropical genus in the Hymenochaetaceae (Basidiomycota, Hymenochaetales), Phytotaxa 261 (3), pp. 218-239 : 222-224

Phellinotus Drechsler-Santos, Robledo & Rajchenb. gen. nov.

Typus generis:— Phellinotus neoaridus Drechsler-Santos & Robledo.

Mycobank no:—MB804717

Etymology:—“ Phelli ” from Phellinus + “ notus ” (ear) from Inonotus , in reference to Phellinus s.l. and Inonotus s.l., which traditionally were considered dimitic and monomitic, respectively. Phellinotus combines both dimitic and monomitic hyphal systems in different parts of basidiomata.

Diagnosis:—Basidioma pileate, annual to perennial; hymenophore poroid. Hyphal system dimitic with skeletal hyphae found only in trama of tube layer; generative hyphae with simple septa, skeletal hyphae aseptate. Basidiospores ellipsoid, adaxially flattened, thick-walled, pale yellow, becoming chestnut brown in KOH solution. Setae and cystidioles absent.

Description: —Basidioma annual to perennial, pileate, applanate to ungulate, fulvous brown to dark brown. Pileus brown to blackened, rugose to rimose. Context with a black line near/below the upper surface, distinct or indistinct. Tubes stratified, with or without contextual tissue layer between them. Hymenophore poroid, pores irregularly rounded, fulvous brown to deep brown. Hyphal system dimitic with skeletal hyphae restricted to the trama of tube layer; contextual generative hyphae in different stages of development, thin- to thick-walled, first regularly septate, branched, becoming sclerified and some portions of thick-walled hyphae sparsely simple-septate; tramal hyphae with simple-septate generative and skeletal hyphae. Setae and other sterile elements absent. Basidia not observed. Basidiospores broadly ellipsoid to ellipsoid, adaxially flattened, smooth, thick-walled, yellow in lactophenol, becoming chestnut brown in KOH solution, weakly cyanophilous, IKI-.

Habitat and distribution:—Found on living members of the family Fabaceae , with host specialization ( Teixeira 1950, Drechsler-Santos et al. 2010, as Phellinus rimosus and P. piptadeniae ). So far known from the South American Seasonally Dry Tropical Forest (SDTF) biome, from the seasonally dry forests of the Atlantic Forest (states of Santa Catarina and São Paulo) and Caatinga (states of Alagoas, Bahia, Ceará, Paraíba, Pernambuco, Rio Grande do Norte and Sergipe) domains of Brazil, and from lowland SDTF of northwestern Peru ( Drechsler-Santos et al. 2010, 2013, Salvador-Montoya et al. 2015).

Remarks:— Phellinotus is characterized by a pileate basidioma often with a rimose pileus, a dimitic hyphal system with skeletal hyphae only present in the trama of the tube layer, and adaxially flattened, ellipsoid, thick-walled, pale yellow basidiospores that turn chestnut brown in KOH solution. The absence of setae and setal hyphae and the presence of colored (pale yellow to brown) and thick-walled basidiospores indicate that Phellinotus is morphologically similar to Arambarria , Aurificaria , Fomitiporella , Fulvifomes , Inocutis , and Phylloporia ( Larsson et al. 2006, Rajchenberg et al. 2015). Fomitiporella and Fulvifomes have a dimitic hyphal system throughout the basidioma, while species of Arambarria , Aurificaria and Inocutis are monomitic. Additionally, some species of Fulvifomes have mainly globose to subglobose, yellowish basidiospores ( Wagner & Fischer 2002), that become ferruginous to fulvous in KOH (5.5‒6 × 4.5‒5.5 μm, as observed in the lectotype of Pyropolyporus robiniae Murrill ), while Phylloporia produces smaller, light yellow basidiospores ( Ryvarden 2004), as observed in the lectotype of P. parasitica Murrill. Fomitiporella also produces basidiospores that turn darker in KOH, as verified in reference material of F. umbrinella , the genus type, collected in the type locality (FLOR49263); however, species in this genus develop resupinate basidiomata and are saprobes ( Murrill 1907, Teixeira 1994, Zhou 2014b) ( Table 1). This morphologically and molecularly related ( Fig. 1 ) group of genera, e.g., Arambarria , Fomitiporella , Fulvifomes , Inocutis , Phylloporia , and other taxonomically unresolved lineages, is named here as the ‘phellinotus clade’. Inonotopsis Parmasto (1973:12) and Pyrrhoderma Imazeki (1966:4) are poroid members of the Hymenochaetaceae that also lack setae and setal hyphae; however, they are phylogenetically unrelated and morphologically differ from members of the ‘phellinotus clade’ by producing thin-walled basidiospores.

Figures

FIGURE 1. Phylogram of Hymenochaetaceae recovered from ITS (ITS1, 5.8S, ITS2) and nucLSU regions, inferred by Maximum likelihood analysis (log likelihood -16996.695988). Support values along branches are bootstrap from ML (≥ 50, before slash) and Bayesian posterior probability (≥0.7, after slash). Trichaptum sector was used to root the tree.