Laura Guzmán-Dávalos

Traditional infrageneric classification of Gymnopilus is not supported by ribosomal DNA sequence data

The traditional classification of Gymnopilus (Agaricales) recognizes two primary groups, Annulati and Gymnopilus, based on the presence or absence of a membranous partial veil. While our analyses of DNA sequence data from the nuclear ribosomal ITS1–5.8S-ITS2 (ITS) gene supports the monophyly of the genus, these traditional subgroups were not recovered. Five well-supported clades within the genus were identified through these analyses: 1) the spectabilis-imperialis group; 2) nevadensis-penetrans group; 3) a clade formed by G. underwoodii, G. validipes and G. cf. flavidellus; 4) aeruginosus-luteofolius group; and 5) lepidotus-subearlei group. Relationships among these subgroups were not resolved.

Physalis and physaloids: A recent and complex evolutionary history

The complex evolutionary history of the subtribe Physalinae is reflected in the poor resolution of the relationships of Physalis and the physaloid genera. We hypothesize that this low resolution is caused by recent evolutionary history in a complex geographic setting. The aims of this study were twofold: (1) To determine the phylogenetic relationships of the current genera recognized in Physalinae in order to identify monophyletic groups and resolve the physaloid grade; and (2) to determine the probable causes of the recent divergence in Physalinae. We conducted phylogenetic analyses with maximum likelihood (ML) and Bayesian inference with 50 Physalinae species and 19 others as outgroups, using morphological and molecular data from five plastid and two nuclear regions. A relaxed molecular clock was obtained from the ML topology and ancestral area reconstruction was conducted using the DEC model. The genera Chamaesaracha, Leucophysalis, and Physalis subgenus Rydbergis were recovered as monophyletic. Three clades, Alkekengi-Calliphysalis, Schraderanthus-Tzeltalia, and Witheringia-Brachistus, also received good support. However, even with morphological data and that of the DNA of seven regions, the tree was not completely resolved and many clades remained unsupported. Physalinae diverged at the end of the Miocene (∼9.22Mya) with one trend indicating that the greatest diversification within the subtribe occurred during the last 5My. The Neotropical region presented the highest probability (45%) of being the ancestral area of Physalinae followed by the Mexican Transition Zone (35%). During the Pliocene and Pleistocene, the geographical areas where species were found experienced significant geological and climatic changes, giving rise to rapid and relatively recent diversification events in Physalinae. Thus, recent origin, high diversification, and morphological complexity have contributed, at least with the currently available methods, to the inability to completely disentangle the phylogenetic relationships of Physalinae.

In and out of refugia: historical patterns of diversity and demography in the North American Caesar's mushroom species complex.

Some of the effects of past climate dynamics on plant and animal diversity make‐up have been relatively well studied, but to less extent in fungi. Pleistocene refugia are thought to harbour high biological diversity (i.e. phylogenetic lineages and genetic diversity), mainly as a product of increased reproductive isolation and allele conservation. In addition, high extinction rates and genetic erosion are expected in previously glaciated regions. Some of the consequences of past climate dynamics might involve changes in range and population size that can result in divergence and incipient or cryptic speciation. Many of these dynamic processes and patterns can be inferred through phylogenetic and coalescent methods. In this study, we first delimit species within a group of closely related edible ectomycorrhizal Amanita from North America (the American Caesars mushrooms species complex) using multilocus coalescent‐based approaches; and then address questions related to effects of Pleistocene climate change on the diversity and genetics of the group. Our study includes extensive geographical sampling throughout the distribution range, and DNA sequences from three nuclear protein‐coding genes. Results reveal cryptic diversity and high speciation rates in refugia. Population sizes and expansions seem to be larger at midrange latitudes (Mexican highlands and SE USA). Range shifts are proportional to population size expansions, which were overall more common during the Pleistocene. This study documents responses to past climate change in fungi and also highlights the applicability of the multispecies coalescent in comparative phylogeographical analyses and diversity assessments that include ancestral species.

Macromycete phenological approximations in western Mexican forests

Abstract The seasonality of 10 of the most abundant species of macromycetes was studied at 3 sites in west-central Mexico. Collections over 20 years from the Instituto de Botánica of the Universidad de Guadalajara database were used for this study. Two of the sites were pine-oak forests: Mazamitla (70 collections) and Tapalpa (68 collections). The third consisted of an ecotone between subtropical cloud forest and pine-oak forest: Nevado de Colima (91 collections). The 3 sites are close to the tropical region and have a rainy season between late May and October. The development and abundance of fruit bodies were related to the climate and the vegetation of each site. Differences were found at 3 scales for both fructification time and abundance: between sites, between species, and within species at different sites.

Russulaceae Associated with Mycoheterotroph Monotropa uniflora (Ericaceae) in Tlaxcala, Mexico: A Phylogenetic Approach

Abstract — The aim of this study was to explore the systematic position of the fungi associated with the roots of M. uniflora in two localities of Tlaxcala, Mexico, using a phylogenetic approach. Thirty plants were sampled, fifteen from a coniferous forest dominated by Abies religiosa in La Malinche National Park, and fifteen from a mixed conifer-broadleaf forest dominated by Pseudotsuga menziesii in Sierra de Tlaxco. Our ITS analysis confirms the preference of M. uniflora to associate with Russulaceae, in particularly with Russula species. The roots of each plant were associated with a single fungal ITS sequence. They were analyzed phylogenetically by maximum likelihood, and were recovered in 12 moderate to well-supported clades within the genus Russula. In each of these clades only a single Russula species was associated with Monotropa in Mexico, except for clade Integrae for which two Mexican species were retrieved. A total of 13 Russula species were retrieved from the 30 Monotropa plants, four from La Malinche National Park, and 11 from Sierra de Tlaxco. Two species, R. aff. olivobrunnea and one unidentified species in subsection Lactarioideae, were shared among both localities. The Monotropa in the Abies forest of La Malinche National Park were dominated by a single species, R. aff. olivobrunnea, present in 11 of the 15 plants. In the Pseudotsuga forest of Sierra de Tlaxco, Monotropa was associated with a higher diversity of Russula, eleven species in total, seven of which were associated with a single plant, while the four other Russula had each been retrieved from two plants. Higher diversity of ectomycorrhizal host trees in the Sierra de Tlaxco site might possibly explain the higher richness of fungal associates as suggested by host association patterns of the involved species groups. This study brings the total number of Russula species that associate with Monotropa to forty-four. In the distribution area of Monotropoideae, nearly all terminal Russula clades (i.e. subsection level) that are involved in this mycoheterotroph association, equally harbor species that associate with mycoheterotroph orchids, whereas gasteromycetation appears to have exclusively evolved in clades that also harbor species developing mycoheterotroph associations.

Some aphyllophorales tested for organic dyes

Fourteen species of Aphyllophorales (Basidiomycotina) were tested for the presence of dyes. The species with the greatest dye potential was Phaeolus schweinitzii , from which five colours, all of excellent intensity, were obtained.

On the Origin of the Genus Psilocybe and Its Potential Ritual Use in Ancient Africa and Europe1

On the Origin of the GenusPsilocybeand Its Potential Ritual Use in Ancient Africa and Europe. The role of altered states of consciousness in the production of geometric and figurative art by prehistoric cultures in Africa and Europe has been hotly debated. Helvenston and Bahn have tried to refute the most famous hypothesis, Lewis-Williams’ neuropsychological model, by claiming that appropriate visual hallucinations required the ingestion of LSD, psilocybin, or mescaline, while arguing that none of these compounds were available to the cultures in question. We present here mycological arguments that tell another story. A prehistoric worldwide distribution of the mushroom genus Psilocybe, and therefore of psilocybin, is supported by the existence of endemic species in America, Africa, and Europe, the disjunct distribution of sister species, and the possibility of long-distance spore dispersal. It is more difficult to point to instances of actual prehistoric ritual use in Africa and Europe, but there are a growing number of suggestive findings.Sobre el Origen del GéneroPsilocybey su Uso Ritual Potencial en África y Europa Antiguas. El papel de los estados alterados de conciencia en la producción de arte geométrico y figurativo por culturas prehistóricas en África y Europa ha sido fuertemente debatido. Helvenston y Bahn han tratado de refutar la hipótesis más famosa, el modelo neuropsicológico de Lewis-Williams, al afirmar que las alucinaciones visuales apropiadas requieren la ingestión de LSD, psilocibina o mezcalina, al mismo tiempo que sostienen que ninguno de estos compuestos estaba disponible para las culturas en cuestión. Presentamos aquí argumentos micológicos que cuentan una historia diferente. La distribución prehistórica mundial del hongo del género Psilocybe, y por ende de la psilocibina, es apoyada por la existencia de especies endémicas en América, África y Europa, por la distribución disyunta de especies hermanas, y por la posibilidad de dispersión de esporas a larga distancia. Es más difícil señalar ejemplos de uso ritual prehistórico reales en África y en Europa, pero hay un número creciente de hallazgos sugerentes.

Gastón Guzmán, 26 August 1932–12 January 2016

Gastón Guzmán (FIG. 1A–H) was a memorable person with a great personality, charisma, and strength of character. He was a cherished father, remarkable teacher, outstanding scientist, and superior mycologist. He died at age 83, working nearly until his death, remaining more active than many much younger mycologists. Guzmán was born in Xalapa, Veracruz, Mexico, although his family lived in Tampico, Tamaulipas, at the time. He was the third of four children, three brothers and one sister, born to his parents, Luis P. Guzmán and Concepción Huerta. When he was 2 years old, an unprecedented flood inundated Tampico. Because of the unhealthy conditions, he became very ill and the entire family moved to Mexico City, where medical care was better. There he completed his undergraduate and postgraduate studies. Guzmán began research as a biologist in 1953, when he was a thirdyear student at the university. He searched for yams (Dioscorea spp.) in the southeastern rainforests of Mexico for the pharmaceutical company Syntex and from Guatemala to Nicaragua for Pfizer in 1954. He then collected hallucinogenic mushrooms for the Swiss pharmaceutical company Geigy from 1956 to 1957. He attended the Escuela Nacional de Ciencias Biológicas (ENCB) of the Instituto Politécnico Nacional, obtaining his bachelor’s degree in biology with honors in 1959. His thesis was on the genus Psilocybe, which had been discovered as a hallucinogenic mushroom only recently. He met Rolf Singer in 1957 and worked for him during a field expedition to the Mazatec region, searching for hallucinogenic mushrooms. As Guzmán often proudly recounted, Singer was the advisor who encouraged him to pursue a career as a mycologist. In 1965, he spent a few months at the University of Michigan, funded by grants from ENCB, the Organization of American States, and the University of Michigan. He received his doctoral degree from ENCB (1967) by the direct option (involving more years of study without acquiring a master’s degree). His dissertation was a monograph on the “earthball” genus Scleroderma, directed by Alexander H. Smith from the University of Michigan and Jerzy Rzedowski, a prominent Mexican botanist from ENCB. In 1956, he was hired by ENCB as a laboratory assistant and kept working while he completed his studies. From 1958, he worked as a teacher and researcher in the same institution, until he moved to the Instituto Nacional de Investigaciones sobre Recursos Bióticos (INIREB) at Xalapa in 1982. From 1988 until his death, he devoted his life to the study of fungi, working at the Instituto de Ecología (INECOL), first in Mexico City and later in Xalapa. In addition to research, Guzmán was concerned with the training of future mycologists and public outreach, establishing collections, and acquiring literature. He invested substantial effort to disseminate information related to fungi, whether by delivering keynote speeches or general talks or by organizing or participating in almost 100 mushroom exhibitions throughout Mexico and Latin America. These exhibitions, in addition to educating the general public, were important for training new mycologists, and he shaped the careers of more than 25 mushroom specialists in Mexico, Guatemala, and Panama. In 1956, Guzmán met Dr. Teófilo Herrera from the Universidad Nacional Autónoma de Mexico (UNAM), then the only mycologist in Mexico. In 1961, they published together the first illustrated catalog of edible Mexican mushrooms with black and white photographs, which remains an essential reference. They founded the Mexican Mycological Society (SMM) in 1965, and later, in 1990, Guzmán founded the Latin American Mycological Association in Havana, Cuba. He was the editor of the SMM journal, Revista Mexicana de Micología, now Scientia Fungorum, for 20 years. With support from Richard Evans Schultes, Guzmán was awarded a Guggenheim Memorial Foundation

Evaluación del efecto tóxico de hongos Basidiomycota en la eclosión de quistes de Artemia franciscana

BACKGROUND The consumption of wild mushrooms has increased in recent years. However, not all mushrooms are edible and some of them may cause poisoning. Therefore, their toxicity needs to be studied. Artemia franciscana is a crustacean used in toxicity tests including toxins of fungi. AIMS To determine the percentage of inhibition and mortality produced by extracts of several basidiomycetes on the hatching of A. franciscana cysts. METHODS Aqueous extracts were prepared from 15 species of mushrooms collected from Jalisco state, Mexico. Different concentrations of the extracts were assayed in order to test their toxicity. Potassium dichromate and artificial seawater were the positive and negative controls, respectively. The percentages of hatching and mortality of the cysts were evaluated. RESULTS Inhibition of hatching greater than 80% in all the concentrations tested was found in 13 of the 15 species studied, in contrast to the positive control, which inhibited cyst hatching less than 50% in all cases. The highest percentage of mortality in the cysts was caused by the aqueous extracts of Amanita virosa, Leucopaxillus amarus, and Tylopilus violatinctus, and the lowest by Macrolepiota mastoidea. CONCLUSIONS The brine shrimp bioassay appeared to be useful in the evaluation of the toxicity of several basidiomycetes, with the exception of Scleroderma texense, a mushroom considered poisonous, which showed no toxicity over A. franciscana.

A new stipitate species of Crepidotus from India and Thailand, with notes on other tropical species

ABSTRACT A new Asian species of Crepidotus (Basidiomycota, Agaricales), C. asiaticus, is presented based on morphological and nuc rDNA internal transcribed spacer (ITS1-5.8S-ITS2 = ITS) and large subunit (28S) sequence data. This new species, found in India and Thailand, is characterized by the centrally stipitate medium-sized basidiomata, orange to reddish brown pileus, white to brownish orange lamellae, and white stipe. Based on morphology, C. asiaticus is similar to the neotropical C. thermophilus. However, the microscopic characters, especially the size and shape of the basidiospores, can be used to distinguish these two taxa, as well as their geographic distributions. Further, the phylogenetic position of C. asiaticus is unique based on ITS and 28S nuc rDNA sequences. Melanomphalia argipoda, described by Singer from Ecuador, is also a stipitate Crepidotus based on an ITS sequence of the type specimen, so the new combination is proposed here. Phylogenetically, the three species form a monophyletic group with the Asiatic C. asiaticus forming the sister lineage to the neotropical C. argipodus and C. thermophilus.