Introduction

The Tamaulipas biogeographic province in the area of the Gulf of Mexico coast is distributed in around 200 000 km², from Northern Mexico to southern Texas, in the United States of America (^{Conabio, 2021}). It is made up of scrub of several types (^{González, 2003}). The thorny scrub has plant species that are 1-4 m tall and grow at altitudes of 100-650 m. The submontane scrub is home to sub-armless trees 4-6 m tall, located in the lower parts of the Sierra Madre Oriental in an east-west direction, between 650 and 700 masl. Both types of scrub include multipurpose plants that are used in rural communities (^{Alanís, 2006}; ^{Estrada et al., 2014}). People use them as round wood for the construction of houses and fences, as well as for the manufacture of domestic furniture, agricultural tools, such as charcoal or firewood, and they consume the fruits of some wild species (^{Alanís, 2006}).

The clearing of scrubs for the introduction of grass and livestock for agricultural purposes or for the production of orange trees is a common practice that causes a dramatic loss of biodiversity (^{Pando et al., 2014}), which disappears without being scientifically known. Such is the case of many macro and micro fungi that recycle organic matter.

Some studies in which species of macrofungi have been recorded in Northern Mexican scrub, for example: Favolus brasiliensis (Fr.) Fr., Polyporus alveolaris (DC.) Bondartsev & Singer, Montagnea arenaria (DC.) Zeller, Podaxis pistillaris (L.) Fr., Phellorinia herculeana (Pers.) Kreisel and Tulostoma Pers. spp., are those of ^{Castillo and Guzmán (1970)}, ^{Esqueda-Valle et al. (1995)} and ^{Esqueda et al. (2012)}. Up to day, there are no reports of macromycetes associated with sensu lato scrub in Northeast Mexico. The objective of this study was to generate information about the species of macromycetes that grow in some scrublands of Northeast Mexico.

Materials and methods

The mushrooms were collected during the last 35 years in more than 100 locations in the states of Nuevo León and Tamaulipas. The classic protocols for the study of macrofungi were followed, which include recording their macroscopic characteristics in situ in fresh specimens (^{Largent et al., 1973}; ^{Villarreal and Gómez, 1995}; ^{Lodge et al., 2004}; ^{Bessette et al., 2016}). Likewise, the characteristics of the collection sites in the field were noted: altitude, condition of the vegetation, tree, shrub and herbaceous species. Photographs (D3300 Nikon^® camera, 40mm macro lens) of the specimens were taken both at a distance of 1 m, and with macrophotography in order to have the maximum details of the sporomes.

For the microscopic visualization of the different structures that characterize the species, fine cuts were manually made with a knife. These were mounted in KOH reagent (5 %) and Melzer in order to observe the contrast of the structures more clearly (^{Largent et al., 1977}).

For color terminology, the Methuen Handbook of Color (^{Kornerup and Wanscher, 1978}) was used. At least 30 microscopic structures (basidiospores, basidia and pileipellis) were measured with an Axiostar Carl Zeiss^® optical microscope (^{Quiñónez et al., 2008}). The Q ratio, mean length (L) and mean width (W) were obtained for basidiospores as described by ^{Frank et al. (2020)}.

The identification of the possible hosts with which the saprobe, parasitic and mycorrhizal species were observed was carried out in the CFNL herbarium of the Graduate School of Forest Sciences of the Universidad Autónoma de Nuevo León in Linares, Nuevo León. The studied material was deposited in the mycological collections of the José Castillo Tovar (ITCV) of the Technological Institute of Ciudad Victoria and the CFNL herbaria. Species were ordered according to ^{Kirk et al. (2008)}; for the classification of the species the ^{Index Fungorum (2023)} was used.

Results

In the present investigation, only a part of the diversity of macromycete species that have been determined associated with the scrublands of Northeast Mexico is documented (Figure 1). The records corresponded to 210 species of Ascomycetes and Basidiomycetes, represented in 138 genera of 57 families, in addition to eight species of Myxomycetes from seven genera belonging to five families in the states of Nuevo León and Tamaulipas. In both states, 186 were distributed, 23 only in Tamaulipas and nine only in Nuevo León. 34 species of them are new records for Northeast Mexico (Table 1).

Frequent species: A = Ganoderma lobatum (Cooke) G. F. Atk.; B = Trametes versicolor (L.) Lloyd; C = Lysurus periphragmoides (Klotzsch ex Hook.) Dring; D = Heliocybe sulcata (Berk.) Redhead & Ginns. Rare species: E = Agaricus deserticola G. Moreno, Esqueda & Lizárraga; F = Pluteus petasatus (Fr.) Gillet; G = Phellodon fibulatus K. A. Harrison.

Figura 1 Some of the macrofungi species found in the shrublands of Northeast Mexico. 

Basidiomycetes were the most diverse, with 187 species from 125 genera and 50 families. The Ascomycetes followed with 23 species, 13 genera and seven families; and the Myxomycetes (previously considered fungi) are represented by five families, seven genera and eight species. The Boletaceae, Agaricaceae, Polyporaceae, and Hymenochaetaceae families presented 14, 13, 10, and eight genera, respectively; and the rest had less than ten. The families with the greatest richness were: Agaricaceae 24, Boletaceae 21, Polyporaceae 21, Xylariaceae 14, Hymenochaetaceae 12, Amanitaceae ten, the rest with less than ten. Of the genera, Xylaria Hill ex Schrank had 14 taxa, Amanita Dill. ex Boehm. ten, Lactarius Pers. and Lentinus Fr. six, Ganoderma P. Karst., Phellinus Quél. and Geastrum Pers. four, Boletus Tourn. three, and the rest less than three.

Discussion

In Mexico, there are few studies on thorny scrub macrofungus species that have been published. This study is the first to attempt to show the great diversity of macromycete species that inhabit the scrublands of Northern Mexico. One of them is carried out in the Northwestern zone of the country in the states of Sonora and Chihuahua, where some species of gasteroid macromycetes (macromycetes with fruiting bodies with intermediate forms from epigeous to hypogeous) were recorded, e. g. that grow associated with native vegetation (^{Esqueda et al., 2006}, ²⁰¹²; ^{Moreno et al., 2007}, ²⁰¹⁰).

In the present study, 218 species of macrofungus associated with the scrublands of Northeast Mexico were obtained for the first time. Of these, 34 species are new records for Northeast Mexico. Some of the taxa agree with those cited from temperate forests at the foot of the mountain by ^{Garza et al. (2019)}. Likewise, some of the species studied here were indicated by various authors for their edibility or growth habit (^{Castillo and Guzmán, 1970}; ^{García et al., 1986}; ^{García, 1993}; ^{Garza-Ocañas, 1993}).

In regard to the medicinal potential of some of the species studied, there is a coincidence with those referred to by ^{González et al. (2009)} (Ganoderma spp.). Hortiboletus rubellus (Krombh.) Simonini, Vizzini & Gelardi, Pisolithus tinctorius (Mont.) E. Fisch. and Scleroderma cepa Pers. are species referred to here that have forestry potential to inoculate oaks in nurseries to plant them in urban areas, since they quickly form abundant mycorrhizae; this agrees with what was described by ^{Garza et al. (2022)} for Boletus luridellus (Murrill) Murrill. This study considers some plants that might form ectomycorrhizae with fungal species, but there are no previous records of such associations. Therefore, it is necessary to carry out the synthesis of mycorrhizae under controlled conditions to verify it, as part of another more precise investigation in this regard. Among some fungi that are suspected to form mycorrhizae with plant species such as Cordia boissieri is Phlebopus brassiliensis Singer.

From the diversity of plant species with which parasitic fungal species or possible mycorrhizal fungi are associated, it was decided to include only the main ones. It is worth mentioning that the diversity of macromycetes is high in this region and it is intended to be published in several scientific articles. The foregoing is the large extension occupied by the scrubs, the few mycologists in the region and the uncertainty of the occurrence of rain in the region due to climate change.

Other studies on the diversity of macrofungus species from different regions and types of vegetation in the country highlight their ecological and functional importance, as well as their edibility, medicinal properties, or biotechnological potential (^{Quiñónez et al., 2008}; ^{Pérez-López et al., 2015}).

The change in land use leads to disturbances and fragmentation of the scrub habitat and this is referred to as one of the main problems facing the diversity of macrofungus in Northeast Mexico (^{Alanís, 2006}; ^{Pando et al., 2014}). ^{Esqueda-Valle et al. (1995)} and ^{Esqueda et al. (2006}, ²⁰¹²⁾ refer to some species of gasteroid fungi from thorny scrub in northwestern Mexico and some of the genera that stand out -Battarrea Pers., Cyathus Haller, Chlorophyllum Massee, Disciseda Czern., Montagnea Fr., Podaxis Desv., Phellorinia Berk., Tulostoma Pers.- coincide with those of the present study. Some of the gasteroid species reported by ^{Moreno et al. (2010)} and ^{Esqueda et al. (2012)} also grow in arid areas where there are scrublands in Northeast Mexico.

Conclusions

The results obtained demonstrated that there is a great diversity of macrofungi in the sensu lato scrublands of Northeast Mexico, however, although there are many more species that have been studied, only a few are listed here. Likewise, there are many more species to be studied that are associated with this ecosystem, which is why even more research is required and that in the future the areas of post-agriculture and post-livestock regeneration are included to generate more information about the pioneer species in this type of vegetation.