Additions to the knowledge of the genus Helvella in Europe: new records and de novo description of five species from the Nordic region

Helvella is a species-rich genus, forming a large variation of astounding ascocarps in many different habitats. During the last decade, molecular markers and morphological characters have been combined to delimit and identify cryptic species in this genus. We report on a list of 54 species of Helvella s.s. in the Nordic region and describe five new species, i.e. H. bresadolae, H. convexa, H. japonica, H. nordlandiae and H. oroarctica. The morphological and molecular characteristics of the new species and the emended / hypocrateriformis, / fibrosa-macropus, and / fallax-pezizoides lineages of Helvella s.s. are shortly commented upon. Further, we include a discussion of the distribution of species in the Nordic region based on a large set of studied collections. The ecological versatility and variable geographic patterns of these species indicate that cryptic species may have contrasting ecology in their local habitats.

Methods
DNA from individual specimens was extracted using the E.Z.N.A.®HP Fungal DNA Kit (Omega Biotek D3195), following the slightly modified procedure from Skrede et al. (2017). The three genetic markers, heat shock protein 90 (hsp), RNApolymerase II second largest subunit (rpb2) and nuclear ribosomal large subunit DNA (LSU) were amplified using PuReTaq Ready-To-Go PCR Beads (GEhealthcare, Waukesha, WI), and purified with 10´ ExoSAP-IT (GEhealthcare, Waukesha, WI). For primer sequences, detailed PCR conditions, and sequencing techniques, see the procedures in Skrede et al. (2017). In addition to sequences produced in the present study, sequences from a representative selection of Helvella species were downloaded from GenBank and included for reference. The sequences were automatically aligned using the MUSCLE v. 3.8.425 (Edgar 2004) plugin in Geneious Prime v. 2019.2.3 (Biomatters, Auckland), followed by manual inspection.