A monograph of <I>Otidea</I> (<I>Pyronemataceae, Pezizomycetes</I>)

Abstract

The easily recognised genus Otidea is subjected to numerous problems in species identification. A number of old names have undergone various interpretations, materials from different continents have not been compared and misidentifications occur commonly. In this context, Otidea is monographed, based on our multiple gene phylogenies assessing species boundaries and comparative morphological characters (see Hansen & Olariaga 2015). All names combined in or synonymised with Otidea are dealt with. Thirty-three species are treated, with full descriptions and colour illustrations provided for 25 of these. Five new species are described, viz. O. borealis, O. brunneoparva, O. oregonensis, O. pseudoleporina and O. subformicarum. Otidea cantharella var. minor and O. onotica var. brevispora are elevated to species rank. Otideopsis kaushalii is combined in the genus Otidea. A key to the species of Otidea is given. An LSU dataset containing 167 sequences (with 44 newly generated in this study) is analysed to place collections and determine whether the named Otidea sequences in GenBank were identified correctly. Fourty-nine new ITS sequences were generated in this study. The ITS region is too variable to align across Otidea, but had low intraspecific variation and it aided in species identifications. Thirty type collections were studied, and ITS and LSU sequences are provided for 12 of these. A neotype is designated for O. cantharella and epitypes for O. concinna, O. leporina and O. onotica, along with several lectotypifications. The apothecial colour and shape, and spore characters are important for species identification. We conclude that to distinguish closely related or morphologically similar species, a combination of additional features are needed, i.e. the shape of the paraphyses, ectal excipulum structure, types of ectal excipulum resinous exudates and their reactions in Melzer’s reagent and KOH, tomentum and basal mycelium colours and exudates. The KOH reaction of excipular resinous exudates and basal mycelium are introduced as novel taxonomic characters.

Species limits and relationships within <I>Otidea</I> inferred from multiple gene phylogenies

“…‘b’), represented by single collections, could not be tested, they were considered to be distinct because they were all genetically divergent from their sisters. For O. daliensis and O. unicisa , LSU and ITS sequences from one or two additional collections were available from GenBank and our LSU analyses support these as monophyletic groups ( Olariaga et al 2015 ). The 33 species recognised here, by genealogical concordance or genetic divergence, can all be recognised by a combination of morphological features (excluding the three putative species in the O. alutacea complex).…”

“…We collapsed these subgroups into a single species, as the branches were short and we believe their reciprocal monophyly may be compromised with the addition of further collections from other geographic areas. Also the minor morphological features used to differentiate O. angusta from O. nannfeldtii did not correlate with the groupings, and we placed O. angusta in synonymy with O. nannfeldtii ( Olariaga et al 2015 ). Otidea bufonia contained two subgroups that reflected the geographical origins of the collections.…”

“…The ITS region showed overall low intraspecific variation. The additional new ITS and LSU sequences are given in Olariaga et al (2015) . Of the 89 collections included in the combined dataset, 16 collections lack RPB1, 8 RPB2 and 9 EF-1α ( Table 1 ).…”

“…The ITS of the O. myosotis holotype and the French collection (NV 2008.09.28) were identical and the epitype ITS sequence of O. leporina differed only 2 bp from those. Five new species were identified: O. borealis , O. brunneoparva , O. oregonensis , O. pseudoleporina and O. subformicarum ; they are described in Olariaga et al (2015) . Otidea cantharella var.…”

“…Our detailed species descriptions, illustrations and a key for identification are given in Olariaga et al (2015) .…”