Entoloma

Montañez, Diego, Noordeloos, Machiel E., Rodríguez, Olivia, Vargas, Ofelia & Guzmán-Dávalos, Laura, 2016, Notes on the genus Entoloma (Basidiomycota, Agaricales) in two volcanic areas of Jalisco, Mexico, Phytotaxa 277 (3), pp. 211-236 : 211-212

Studying Entoloma from Mexico: problems and limitations

Our study of the Entoloma species of Jalisco State is essentially a pioneering one. Not much is known of the occurrence, ecology, and distribution of members of the genus Entoloma in Jalisco state. This applies not only for Jalisco, but for the whole of Mexico generally. Information on Entoloma and its Mexican representatives is mostly confined to local inventories, usually without much information on the morphology or ecology. Thus, for our study of the genus Entoloma in Jalisco State we had to rely on extralimital literature in an attempt to sort out our material. Since many species of Entoloma have been found in Jalisco in the extensive Quercus-Pinus forests on higher elevations, and to a minor degree in deciduous and (sub-) tropical forest, we expected to find similarities with the Entoloma species of the Southern and South-western parts of the United States, and to a lesser extent, with that of tropical Central- and South America. Despite that, it appeared often very hard to find matching descriptions.

For various reasons, we also had to decide that our study should be restricted to the traditional morphological concept. Molecular studies, albeit very much in vogue nowadays, are expensive, and, in the case of older herbarium collections, also prone to a low success rate. An additional and more relevant problem with molecular studies is the lack of reference material for the genus Entoloma . ITS sequence databanks, such as GenBank, contain only a very small part of the vast number of existing Entoloma species, and in too many cases, the identification of these accessions is questionable. Barcodes of types are scarce, in particular those of the species described by North American authors, such as Hesler and Peck. So even if we had barcodes of our taxa, then it would still have been very hard to match them with any of the known species. For these reasons, we have retained the morphological species concept, which has strong roots and proven itself in mycological taxonomic tradition. A final issue, which is quite important, lies in the fact that collections from one to another location almost always show some degree in variability of their morphological characters. Thus, it will always contain a certain amount of subjectivity to decide whether a particular collection can be identified as a known species, or represents something that has not been described in literature.

During our studies of the Entoloma material of Jalisco, we have been confronted in several cases with the fact that few collections matched to a great extent with a North American species that was only known from the type locality. Usually, and naturally, there was always some variation that had to be considered, which is mentioned in the notes following the descriptions. Our description, being solely based on observation on the Mexican material, therefore may serve as a good starting point for describing infraspecific variability, or eventually be the base of the description of the new taxon, in case additional specimens allow a better interpretation of that variability. One could have opted in those cases for a “cf.” identification, stressing the similarity with a known taxon, but acknowledging the doubt whether this also means that the collection is conspecific with that known taxon. Or, the other way round, we could have chosen to describe all collections as new taxa. Both approaches have been followed here.

Our main goal is to describe the Entoloma species of Jalisco State and publish an account, with identification tools, to raise interest for this biologically interesting group in Mexico, and to stimulate further studies. Specifically, this work described, based on morphological characters, some species of Entoloma of two volcanos in the state of Jalisco, Mexico, the Nevado de Colima and the Tequila volcano.