Type studies in Helvella (Pezizales) 1

Sixteen type and some additional specimens representing fifteen species assigned to Helvella were studied with the aim of providing new data for their improved delimitation and recognition. Specimens were received on loan from DAOM, FH, H, K, MA, MICH, S and UPS. A synoptic key to the studied species is provided to contribute to a better understanding of the genus and the taxonomy of the morphospecies. Original descriptions are emended to include data on the anatomy of the apothecial excipulum and stipe layers, apothecium and stipe reactivity to Melzer's reagent, and ascospore ornamentation. Reasons are given for maintaining H. subglabra, H. atra, H. griseoalba, and H. costifera as independent taxa and for considering Helvella hyperborea a synonym of H. costifera. Previously imprecise descriptive terms are clarified.