Rajchenbergia Salvador-Montoya, Popoff & Drechsler- Santos, gen. nov.

Index Fungorum number: MB 830786; Facesoffungi number: FoF

TYPE: Rajchenbergia pertenuis (Xavi- erDeLima & Oliveira-Filho) Salvador-Montoya, Popoff & Drechsler-Santos (combined below)

Etymology: Rajchenbergia, in honor of Dr. Mario Rajchen- berg for his important contribution as a mycologist, and especially for his works on polypores.

Diagnosis: Basidioma annual, effused, hymenophore poroid. Subiculum thin, homogenous o with a dark line. Hyphal sys- tem monomitic with generative hyphae simple septate. Setae and cystidioles absent. Basidiospores ellipsoid, broadly ellipsoid to ovoid, thick-walled, yellowish to rusty brown.

Description: Basidiomata annual, effused, woody hard when dry, subiculum thin, homogenous or with a darker line just above the tubes, pore surface not cracked when dry, hyphal system predominately monomitic, generative hyphae sim- ple septate, branched, thin-walled to gradually thick-walled, setae absent, cystidioles absent, basidiospores ellipsoid, broadly ellipsoid to ovoid, thick-walled, smooth, yellowish to rusty brown, positive or negative in cotton blue, negative in Melzer’s reagent.

Habitat and distribution: The species of genus are found predominately on deciduous wood of angiosperms. This genus is distributed mainly in the tropical climatic zones.

Notes: – Rajchenbergia is characterized by effused basidio- mata, often with a dark line between context and tubes, pre- dominately monomitic hyphal system and colored basidio- spores. The effused basidiomata and yellowish basidiospores indicate that Rajchenbergia is morphologically similar to Fomitiporella and Arambarria. Nevertheless, Fomitiporella and Arambarria present effused-reflexed basidiomata.

Additionally, Fomitiporella has a homogenous context and dimitic hyphal system, while Arambarria presents a rudi- mentary mycelial core in the base of basidiomata (Rajchen- berg et al. 2015; Drechsler-Santos et al. 2016; Pildain et al. 2017) (Table 2). In our results Phellinotus is a sister group of Rajchenbergia; however, Phellinotus have pileate basidi- omata with the monomitic hyphal system in the context and a dimitic hyphal system in the trama of tubes (Drechsler- Santos et al. 2016). Among the species of Rajchenbergia, R. tenuissima was described with a monomitic to dimitic hyphal system in the basidiomata, with skeletal-like hyphae similar to generative hyphae (rarely septate), besides the generative hyphae (Yu et al. 2013, as Inonotus tenuissimus Y.Yu, C.L.Zhao & Y.C.Dai). Nevertheless, other genera in the Hymenochaetaceae such as Arambarria, Fulvifomes and Tropicoporus present regularly septate generative hyphae slightly thick-walled with a wide lumen, that also resem- ble skeletal hyphae (Rajchenberg et al. 2015; Zhou et al. 2016; Salvador-Montoya et al. 2018a). In this case, based on the literature, we considered these skeletal-like hyphae as generative hyphae. The other two species of Rajchenber- gia, R. mangrovei and R. pertenuis, were described as hav- ing basidiomata with a monomitic hyphal system (Ji et al. 2017; Crous et al. 208). Therefore, we described Rajchen- bergia predominately with monomitic hyphal system in the basidiomata.