Monte Desert Of Argentina Research Articles

Longevity records for bird species from the central Monte desert, Argentina

ABSTRACT Longevity is a key life-history parameter of bird species, highly relevant for the development of evolutionary biology, the study of ecological patterns and conservation planning. However, there is a marked paucity of data for Neotropical birds, mainly because estimating longevity requires long-term studies that are very scarce in temperate South America. We report data on the longevity of 25 bird species obtained in an 8-year long-term capture–recapture programme carried out in the Monte desert in Argentina and evaluate the influence of diet and migratory status on this life-history trait. The maximum value recorded was 105 months for Microspingus torquatus and the minimum was 13 months for Synallaxis albescens. Resident birds had higher average longevity than migratory birds, while species consuming mainly plant material had higher longevity values than those consuming mainly animal foods. Our results are similar to the few published records from temperate South America, although more data are needed to assess the impact of diet and migratory behaviour on longevity of Neotropical species.

Effect of road disturbance on ant diversity in the Monte desert of Argentina

Effect of road disturbance on ant diversity in the Monte desert of Argentina

Effect of hydrocarbons on the germination of Larrea divaricata and Pappostipa speciosa in the Monte Desert of Argentina

In Monte Desert, one of the most arid regions in Argentina, there is an important hydrocarbon basin and the main shale oil reservoir in South America. An intense oil activity takes place there through rock fractures, where failures and spills can occur. Loss of hydrocarbons due to high pressure conditions, produce emissions into the air in the form of sprays that can be deposited in large areas on the ground (blow outs). In samples of uncontaminated soil and soils affected by a blow out event we evaluated seed germination under laboratory conditions of keystone species: Larrea divaricata Cav. and Pappostipa speciosa (Trin. & Rupr.) Romasch. In uncontaminated controls, germination probabilities varied between 0.55 and 0.66 for L. divaricata and between 0.76 and 0.86 for P. speciosa. In contrast, in contaminated soils, germination probability was significantly lower for both species: 0.01–0.02 for L. divaricata and 0.2–0.25 for P. speciosa. We conclude that the presence of hydrocarbons significantly decreases germination of the studied species. Therefore, natural regeneration in arid regions can be seriously affected by hydrocarbon spills.

Experimental assessment of endozoochorous dispersal of Prosopis flexuosa seeds by domestic ungulates

AbstractQuestionThe spatial and temporal dynamics of plant communities in various ecosystems are shaped by the movements of seeds expressed as different dispersal modes. In desert rangeland, many plants produce relatively large fruits that are limited in their long‐distance dispersal abilities and, therefore, depend on transport inside animals, a process termed endozoochory. Evaluating the effectiveness of this process from experimental data is crucial for assessing the potential of domestic ungulates as effective long‐distance seed dispersers and, consequently, as management and restoration tools in degraded rangelands.MethodsIn this study we jointly estimated recovery, gut retention time (RT) and germination probability of Prosopis flexuosa seeds (a tree species of Monte desert in Argentina) transported by goats, horses and cattle (n = 4) through a seed‐feeding experiment. Also, in horses and cattle, we used plastic particles to distinguish between seed loss due to mastication and due to degradation in the gut.ResultsResults showed higher seed recovery in horses (26%) than in cattle (3%) and goats (5%), and different values of RT and germination of seeds among species (in decreasing order, RT was: cattle > goats > horses; and germination was: goat > horses > cattle = control seeds).ConclusionsWe concluded that the quality of seed treatment by horses is better than by the other species, because of the high seed recovery and high germination compared to control seeds. To get a complete picture of this mutualistic interaction, future studies could inquire about the physical and chemical properties of faeces as substrate and the environmental conditions of sites where seeds are deposited.

Winter Irruption of Two Geranoaetus Hawks in the Monte Desert of Argentina

ABSTRACT Winter irruption refers to an unpredictable increase in the number of individuals usually dominated by one age class, either juvenile or adult, into a given area as a response to fluctuations in the food supply. Irruptions are well documented for avian predators breeding in the Arctic and Subarctic regions whereby individuals irrupt into irregular nonbreeding areas across the Boreal Temperate Region. However, this phenomenon is largely unknown across the Austral Temperate Region. We studied the age class composition of Variable Hawks (Geranoaetus polyosoma) and Black-chested Buzzard-Eagles (G. melanoleucus) during six austral winters (nonbreeding season) at an overlapping breeding and overwintering area in the Monte Desert (semiarid grassland and shrub steppes) of the Andean foothills at Mendoza province in central Argentina (33°S). We measured the overall abundance per winter (combining the five age classes) and calculated the relative abundance per age class for each winter of both species. We used the ratio of total number of individuals observed in a single winter/the total hours of observation per winter as an index of abundance, because sampling effort was not equal across winters. We found that (1) both species exhibited winter irruptions, (2) the irruptions were largely driven by a marked increase of Basic I individuals (the youngest age class); at the same time, Basic V individuals (the oldest age class) exhibited their (modestly) lowest abundance, and (3) winter irruptions might be species-specific, as the responses differed between the two species, with a joint irruption event in the austral winter 2016 and a second irruptive event only recorded for Black-chested Buzzard-Eagles in the austral winter of 2018. We posit that the marked increase of Basic I individuals during the irruptive winters cannot be fully explained by successful breeding of the local population, and is likely largely a result of individuals born elsewhere, presumably at southern latitudes, and overwintering at our study site in central Argentina.

Importance of Algarrobo Trees Prosopis flexuosa for Territory Establishment of Three Seed-Eating Passerine Species in the Central Monte Desert

In the central Monte desert in Argentina, feeding site selection by seed-eating birds and their high abundance associated with the presence of trees (particularly Algarrobos Prosopis flexuosa) are well known patterns during the breeding season, but these associations disappear during autumn and winter. In order to understand habitat selection by these bird species, we assessed the importance of Algarrobos during the defence and establishment of breeding territories in the open Algarrobo woodland of the central Monte desert for the three most common resident seed-eating birds: Ringed Warbling-finch Microspingus torquatus, Many-coloured Chaco Finch Saltatricula multicolor and Rufous-collared Sparrow Zonotrichia capensis. Despite some ecological differences between the species (e.g. nest site selection, feeding behaviour) all of them selected Algarrobos as song posts. Height, density and spatial configuration of these trees were features associated with the selection of territories. The patterns of selection we found at previously unexplored spatial scales (territory and within-territory) and associated with territorial defence, provided plausible explanations to seasonal shifts in the space use reported for central Monte desert seed-eating birds and highlight the close link between central Monte desert avifauna and Algarrobos. As in many arid regions, tall scattered trees are keystone features of the central Monte desert and management plans should be implemented in order to stop the current degradation and loss of these arid woodlands.

Effects of Tourism on the Habitat Use by a Threatened Large Rodent at a World Heritage Site

Simple SummaryThe mara is a large endemic rodent, which major threats are habitat loss, hunting, and overgrazing. Maras live in arid and semiarid areas of Argentina. We studied the influence of environment variables and tourist activity on mara’s habitat use. We used different ecological approaches, from plant communities to floristic composition, in order to know at which level we can better detect the tourism effects on mara’s habitat use. We counted feces of maras as a habitat use index and recorded environmental variables along 80 samples in two plant communities, near and away-from the tourist circuit. To evaluate habitat use, we made statistical models using plant communities, plant strata, cover of trees, shrubs, and grasses, and plant species abundance as explaining factors. We detected the tourism effects on habitat use utilizing cover of trees, shrubs, and grasses, and cover of more abundant plant species, but not plant communities and plant strata, as explicative factors. Maras also selected areas with low bare soil with few pebbles on it. We found complex interactions between abiotic, biotic, and anthropic variables, studying maras’ preferred places near tourism activities, which they probably perceive as safer from predators.The mara is a large endemic rodent, which presents a marked decline in its populations, mainly because of habitat loss, hunting, and overgrazing. The Ischigualasto Provincial Park is a hyper-arid protected area at the Monte Desert of Argentina with an overall low plant cover. Our objective was to determine the influence of environmental variables and tourist activities on mara’s habitat use. We used different biological levels to explain it, from plant community to floristic composition, in order to know at which level we can better detect the effects of tourist activities. We registered fresh feces and habitat variables along 80 transects in two communities, near and far away from the tourist circuit. To evaluate habitat use, we fitted models at different biological levels: plant community, plant strata, plant biological forms, and floristic composition. At the community and plant strata levels, we could not detect any tourism effects on habitat use. However, we detected effects of tourist activities on mara’s habitat use at the plant strata and floristic composition levels. Maras also selected areas with a low proportion of both bare soil and pebbles cover. We found complex interactions between abiotic, biotic variables and tourism, studying mara’s places near tourism activities, probably because they perceive those places as predator-safe areas.

Contributions to the Knowledge of Sexual Dimorphism in Liolaemus darwinii (Squamata, Liolaemi-dae) in the Monte Desert of Argentina

The lizard Liolaemus darwinii (Liolaemidae) is a typical species with wide distribution in Monte environments of Argentina. The objective of this study is contribute to knowledge of sexual dimorphism in a population of L. darwinii (Bell, 1843). We evaluated sexual shape variation of the cephalic region through procustes analyses with geometric morphometry. We predict that the heads in males will have differences in shape with respect to females. The results showed significant sexual differences in shape, mainly in the region around the eyes. There were no significant differences in sizes. Geometric morphometry analyses are a useful tool for addressing sexual differences in Monte lizards. This constitutes the first study for the center-west of Argentina in San Juan province that implements these geometric morphometry analyses.

Parasitic nematodes of reptiles (lizards and snakes) in the Monte Desert of Argentina

Nematodes are little known in the Argentine herpetofauna. In order to increase and contribute to the knowledge of parasitism in reptiles, we studied nematodes found in three species of lizards (Aurivela longicauda, Liolaemus darwinii, and Liolaemus riojanus) and one species of snake (Philodryas trilineata) from the Monte desert of center-west Argentina. We registered generalist nematodes common of the herpetofauna that belonged to two taxa: Physaloptera sp. (Physalopteridae) (larvae and adults specimens) and Parapharyngodon riojensis (Pharyngodonidae) (adults specimens). Liolaemus darwinii had low prevalence of nematodes (30%) and a mean intensity of 1.3±0.4 (1-2). The lizard A. longicauda had higher parasitic diversity with medium prevalence (50 and 12.5%) and mean intensities of 1.3±0.4 (1-2) corresponding to adult stages of Physaloptera sp. and Parapharyngodon riojensis. Due to the low number of studied specimens, precise conclusions cannot be drawn for Liolaemus riojanus and P. trilineata. The four reptile species correspond to new host records from Argentina, and the information provided contributes to the knowledge of endoparasitism in reptiles of the Argentine Monte region.

Spermatogenesis and plasma testosterone levels under field conditions, in males of the common toad (Rhinella arenarum Hensel, 1867), from the Monte Desert, Argentina

The reproductive function in anurans depends on interactions between the hypothalamus, adenohypophysis and gonads, which are mediated by an endocrine circuit. We studied the relationship between reproductive and histological parameters, variation in spermatogenic activity, and plasma testosterone concentration cycle for a population of Rhinella arenarum under field conditions in the Monte Desert of Argentina. We captured 28 adult male R. arenarum from December 2009 to November 2010, and define two seasons (wet and dry seasons). We performed histological analyses of the testes and used radioimmunoassay to determine plasma testosterone concentrations. Our results showed no difference in testicular volume between the wet and dry seasons, but found that changes in the fat body mass were higher in the dry season. The spematogenic cycle was characterized by the prominent presence of spermatogonia at the end of the dry season and the wet season. We also observed a higher percentage of primary spermatocytes in the wet season. In addition, we found that R. arenarum showed a continuous spermatogenic cycle, and spermatogenesis produced a high percentage of sperm bundles in the dry season, concordant with high levels of testosterone. Testosterone levels were highest during the dry season (33.89 ± 7.85 ng/ml). Our data indicate that plasma testosterone showed a “dissociation” from reproductive activity such that the two parameters are asynchronous during the reproductive season. The characteristics of the reproductive cycle of R. arenarum allow this species the plasticity to colonize different environments, from tropical regions to deserts.

Daily Activity Patterns and Thermal Tolerance of Three Sympatric Dung Beetle Species (Scarabaeidae: Scarabaeinae: Eucraniini) from the Monte Desert, Argentina.

Tolerance to extreme temperatures, thermal limits, and the mechanisms of thermoregulation are related to internal functions of insects and partly define their ecological niche. We study the association between daily activity of dung beetles from the Monte Desert in Argentina and their tolerance to high temperatures. Results indicate that for all three sympatric species studied, Eucranium belenae Ocampo, Anomiopsoides cavifrons (Burmeister), and Anomiopsoides fedemariai Ocampo, daily activity is associated to ground temperature. Eucranium belenae is active when ground temperature is relatively low and it is less tolerant to long periods of activity at high temperatures in the lab, while A. cavifrons and A. fedemariai are active when ground temperatures are higher, and they tolerate high temperatures for longer periods of time than E. belenae in the lab. These species coexist and use similar food sources, and this eco-physiological study may help to explain how they differentiate under the same environmental conditions. The Monte Desert is considered an extreme environment, and studies on thermal tolerance offer testable predictions to understand how species would respond to climate change.

Coexisting in harsh environments: temperature-based foraging patterns of two desert leafcutter ants (Hymenoptera: Formicidae: Attini)

Dominant herbivores, like leafcutter ants, have a strong impact on the ecosystems they inhabit. Understanding which factors regulate their foraging rates is crucial for understanding ecosystem dynamics. In desert habitats, environmental factors, such as temperature, play a major role in regulating ants' behavior. We studied the role of ground temperature in regulating daily and seasonal activity patterns of two coexisting leafcutters ant species, Acromyrmex lobicornis (Emery, 1888) and A. striatus (Roger, 1863), in the Monte desert of Argentina. We measured the variations in activity levels and soil temperature every two hours throughout the day in colonies of both species every season for two consecutive years. Temperature was a good predictor of both the timing of colony activation (the onset and end of their daily foraging activities) and foraging intensity (the number of workers devoted to foraging tasks). However, temperature affected each species differently: Acromyrmex lobicornis foraged at lower temperatures (10 - 35 °C) than A. striatus (27 - 45 °C). Our results suggest that these two species have different thermal tolerance ranges that result in temporally separated foraging activities. We suggest that interference competition may have driven this temperature and temporal specialization in these two sympatric species, given their similar sizes and diets. Field observations of activity vs. temperature in allopatry, and behavioral tests in controlled conditions should provide further evidence to test this hypothesis

Patterns of phenotypic selection for oil and nectar in Monttea aphylla (Plantaginaceae) in a geographic mosaic of interactions with pollinators

Oil-flower species are highly specialized attracting a narrow group of oil-collecting bees in contrast to nectar-flower species visited by a wide diversity of pollinators. The vast majority of the oil species lack nectar as a pollinator reward; this suggests that the ancestors of plants with oil flowers had either nectar-less flowers or faced strong selection against the production of nectar once oil secretion evolved. Monttea aphylla is one of the few species that simultaneously offers oil and nectar in the same flower to pollinators. In particular, we studied phenotypic selection in 16 populations in the Monte desert of Argentina that spanned the entire geographical range of the species. In each population, we determined the relationship between plant pollination success and floral rewards. Positive directional selection differentials were detected in three of the populations. One northern population favoured selection on oil production, two central or southern populations favoured selection on nectar production. Directional selection gradients were consistent with the above results and correlational selection was significant for one northern population where pollination success was favoured by an increased selection on oil and a decreased selection on nectar. Geographic variation in phenotypic selection models showed latitudinal increase in directional selection on nectar. Geographic variation in visitation frequencies of the specialist oil-collecting bee and relative abundance of other floral sources were related to an increase in directional selection on nectar. Thus, evolution of rewards appears to respond to a geographic mosaic where either oil or nectar are favoured in different contexts of ecologically specialised oil collecting bees. Although phenotypic selection was detectable in few and was absent in most populations, the general pattern was consistent with current geographic differentiation in reward amounts.

Anthropogenic disturbance impact on the stem growth of Prosopis flexuosa DC forests in the Monte desert of Argentina: A dendroecological approach

Anthropogenic disturbance acts globally as an ecological process with long-term implication on the ecosystem equilibrium. In the central-western Argentina (Desierto del Monte Central: DMC), the desert Prosopis flexuosa woodlands has been intervened by man with differential incidence, e.g. through logging, fire and grazing. Despite recognizing a history of disturbances in these forests, the local removal of trees and its incidence in the stem growth of the surviving trees is still poorly known. Dendroecological methods were applied to 10 plots distributed along a landform gradient, aiming to analyze how disturbance, together with possible modulation effects of the spatial variability on growth, can influence forest dynamics. Tree removal was an intensive practice during the second half of the 20th century in the DCM, in synchrony with the expansion of wine-growing activity. Our results suggest that removal of P. flexuosa individuals in any considered plot was the main driver of changes in the forest dynamics. This argument is based on the weak climatic incidence in years considered critical with respect to the beginning of abrupt tree-growth releases. This disturbance impact seemed to be landform-dependent, as suggested by the higher relative basal area values at mesic sites in relation to sites linked to drier landforms. The presented findings represent the first attempt in reconstructing the disturbance regime experienced by the DMC P. flexuosa woodlands. Our research contributes to interpret how logging practices coupled with landform-related heterogeneities may influence the forest dynamics at desert environments, providing elements for implementing policies for conservation and management of these natural resources.

Seed germination and seedling growth of the geophyticPterocactus tuberosus(Cactaceae)1

Abstract The focus of this study was on seed germination and seedling growth of Pterocactus tuberosus, an endemic cactus inhabiting the Monte desert of Argentina, which possesses unusual winged seeds and geophytic habit. We evaluated the effects of water availability, temperature, and light on germination, and the influence of soil moisture on seedling growth. The effects of water potential were examined using 0, −0.1, −0.4, −0.7, and −1.0 MPa solutions. Temperature treatments included 15, 20, 25, 30, 35, 40, 20/10, 25/15, and 30/20 °C. To assess photoblastism, seeds were exposed to light or continuous darkness. Total germination, weighted germination percentages, and mean germination times were calculated. Plant size and biomass of 1- and 6-wk-old seedlings were determined under high, moderate, and low watering frequency treatments. Results showed that decreasing water potential affected germination, which was about 80% at 0 and −0.1 MPa, and then, decreased to almost complete inhibition at ≤ −0.7 MPa. R...

Response of ants to grazing disturbance at the central Monte Desert of Argentina: community descriptors and functional group scheme

Livestock ranching is one of the main productive activities in arid regions of the world. Grazing produces changes in animal as well as plant communities (e.g. richness, abundance and species dominance relationships). Ants are good biological indicators due to the environmental fidelity of some of their community parameters. We described the functional structure of the ant community in the central Monte of Mendoza, Argentina, and examined the effect of grazing using richness, diversity and the functional group scheme. We used pitfall traps to sample ants at a reserve with 30-year cattle exclusion and at an adjacent ranch. Eleven of the 27 recorded species showed significant differences in their abundance and two species were absent at the ranch. While richness and diversity did not reflect these differences, functional groups did. Hot Climate Specialists were more abundant at the ranch while Cryptic Species and Generalized Myrmicinae increased at the reserve. This study supports the utility of the functional group scheme to study the effects of grazing disturbance in ant communities of arid regions.

Multi-scale patterns of habitat use by wild boar in the Monte Desert of Argentina

A large number of protected areas worldwide have been impacted by biological invasions, threatening the biodiversity they aim to protect. The wild boar (Sus scrofa) is one of the most threatening invasive species in Argentina, already occupying many ecoregions, including the central Monte Desert. However, there are no studies regarding the use that wild boars make of this invaded biome and what factors (climate or landscape) determine or contribute to the establishment of this species. The objectives of this study were to assess habitat use of the wild boar at spatial and temporal scales in the central Monte Desert, and to assess if climatic factors influence its abundance. Our results show that, at habitat-level the wild boar exhibited preferences for a particular habitat (Larrea shrubland) for feeding. At microhabitat-level, we found a positive association between herb cover and wild boar presence. In addition, we found a strong and positive association between the number of days with low temperatures and the number of wild boar signs registered. Therefore, we consider that in the central Monte Desert, habitat selection by wild boars is most likely determined by a maximization of food intake and a minimization of exposure to high temperature.

Effects of leaf-cutting ant refuse on native plant performance under two levels of grazing intensity in the Monte Desert of Argentina

Question Low quantities of soil nutrients often restrict plant establishment and growth in arid lands and have been partially attributed to the scarcity of organic matter in these ecosystems. Refuse dumps from leaf-cutting ants are a natural source of organic matter; however, their effects on native plant performance have received limited attention to date. Do refuse dumps from leaf-cutting ants (Acromyrmex lobicornis) enhance the germination and growth of several native plant species and what is the potential influence of heavy grazing on this practice? Location Monte Desert, Neuquén Province, Argentina. Methods We collected fruits of five plant species and two types of substrate (ant refuse dump vs control soil) from two known paddocks with different livestock densities (high vs low). We sowed seeds, previously weighed, of each species in both substrates from both paddocks and monitored their development. We harvested emerged seedlings, documenting their age and measured their height, weight, number of leaves, root weight and root length. Results Seed weight was lower in the highly grazed paddock for all the plant species studied. However, seed weight did not affect germination rate. Refuse dumps from the less grazed paddock (i.e. with higher nutrient content) enhanced the vigour of seedlings from smaller seeds more often than those from the highly grazed paddock. Also, germination improved when both seeds and substrate were from the less grazed paddock. Vigour variables showed more complex results, but seedlings growing in refuse dumps tended to be more vigorous. Refuse dumps from the less grazed paddock (i.e. with higher nutrient content) enhanced the vigour of seedlings from the highly grazed paddock (smaller) more than the seeds from the less grazed paddock (larger). Conclusions Our results demonstrated that ant refuse dumps increased plant germination rate and improved performance of the most representative vegetation in the Monte Desert. Given that external refuse dumps from leaf-cutting ants are a renewable resource, very abundant and easy to collect, this substrate could be used as a free natural fertilizer in arid regions to restore and manage vegetation cover, especially in heavily grazed sites.

Evaluating sampling completeness in a desert plant–pollinator network

1. The study of plant-pollinator interactions in a network context is receiving increasing attention. This approach has helped to identify several emerging network patterns such as nestedness and modularity. However, most studies are based only on qualitative information, and some ecosystems, such as deserts and tropical forests, are underrepresented in these data sets. 2. We present an exhaustive analysis of the structure of a 4-year plant-pollinator network from the Monte desert in Argentina using qualitative and quantitative tools. We describe the structure of this network and evaluate sampling completeness using asymptotic species richness estimators. Our goal is to assess the extent to which the realized sampling effort allows for an accurate description of species interactions and to estimate the minimum number of additional censuses required to detect 90% of the interactions. We evaluated completeness of detection of the community-wide pollinator fauna, of the pollinator fauna associated with each plant species and of the plant-pollinator interactions. We also evaluated whether sampling completeness was influenced by plant characteristics, such as flower abundance, flower life span, number of interspecific links (degree) and selectiveness in the identity of their flower visitors, as well as sampling effort. 3. We found that this desert plant-pollinator network has a nested structure and that it exhibits modularity and high network-level generalization. 4. In spite of our high sampling effort, and although we sampled 80% of the pollinator fauna, we recorded only 55% of the interactions. Furthermore, although a 64% increase in sampling effort would suffice to detect 90% of the pollinator species, a fivefold increase in sampling effort would be necessary to detect 90% of the interactions. 5. Detection of interactions was incomplete for most plant species, particularly specialists with a long flowering season and high flower abundance, or generalists with short flowering span and scant flowers. Our results suggest that sampling of a network with the same effort for all plant species is inadequate to sample interactions. 6. Sampling the diversity of interactions is labour intensive, and most plant-pollinator networks published to date are likely to be undersampled. Our analysis allowed estimating the completeness of our sampling, the additional effort needed to detect most interactions and the plant traits that influence the detection of their interactions.

Description of a new species of <i>Perichaena</i> (Myxomycetes) from arid areas of Argentina

Lado, C., Wrigley de Basanta, D., Estrada-Torres, A., Garcia Carvajal, E., Aguilar, M. & Hernandez-Crespo, J.C. 2009. Description of a new species of Perichaena (Myxomycetes) from arid areas of Argentina. Anales Jard. Bot. Madrid 66S1: 63-70. A new species of the myxomycete genus Perichaena is described in this paper. The new species, named Perichaena calongei, was found during intensive studies of arid areas of the Monte desert in Argentina. It has been found directly in the field from the provinces of Catamarca, La Rioja, Salta and San Juan, in the Northwest of Argentina, and isolated from moist chamber cultures of native plant species collected in Catamarca, Jujuy, Salta and San Juan. The characters that make this species unique in the genus are the combination of the morphology of the sporocarps, the structure and dehiscence of the peridium, and the ornamentation of the capillitium. The morphology of the my xo mycete specimens was examined using light microscopy with Nomarski interference contrast, and scanning electron microscopy. Micrographs of relevant morphological characters are included. A key to facilitate the identification of the stipitate species of Perichaena is also proposed.