**1. Introduction**

In the upper parts of the Cusco region – Peru, the vegetation is mostly in the form of grasslands and small shrubs, with the genus *Polylepis* (Rosaceae) being the only dominant tree element. These forest patches are vital for protecting the soil against erosion, retain nutrients, sediment, and produce a vital amount of oxygen, and host a unique diversity of birds and plants, among other organisms. Despite their importance, these forests are in danger of extinction due to the growing pressure of the Andean population, as a product of numerous economic, social, and cultural factors [1]. There are several studies carried out on *Polylepis* in terms of flora and fauna in Peru and especially in Cusco, but not so on the epiphytic mosses that are found predominantly in these arboretums.

The *Polylepis* forests in the Urubamba valley constitute one of the largest population concentrations and the largest center of genetic diversity in the Andes with six species of the 10 cited for the national territory, *Polylepis besseri, P. racemosa, P. subsericans, P. pauta, P. sericea,* and *P. microphylla*, the same ones that house a great

diversity of mosses that play a fundamental role in the conservation and maintenance of ecosystems due to their hydrophilicity, responsible for keeping these habitats moist; making necessary to know its diversity.

The Musci are the most complex group within the Bryophytes, not only because of the morphology of their gametophytes but particularly because of the structure of their sporophytes. They make up the group of Bryophytes with the most species; it is estimated that worldwide there are between 8000 and 12,800 species in 900 genera. The number of mosses estimated for the Andean region of Colombia, Ecuador, and Peru is likely to reach around 900950 species. Among these countries, Peru requires more work both in terms of additional inventories and published results; however, around 829 taxa are currently known for the entire territory, of which 797 are reported for the Andean region [2]. There is a gradual increase in the diversity of taxa according to elevation, with a maximum between 2500 and 3000 m, beyond this altitude interval, there is a marked decrease in diversity, notably above 3500 m. Thus, in Bolivia, a greater diversity was recorded between 2000 and 2500 m, followed by the 25003000 m interval [3].

In this regard, Menzel [4] cites 181 species for the department of Ayacucho, the vast majority collected by Hegewald & Hegewald, who carried out explorations in various departments of Peru between 1973 and 1977, including Ayacucho, some were carried out in the province of Huamanga. Opisso [5, 6] carried out an inventory of pleurocarpous mosses in the province of San Ignacio – Cajamarca, registering 40 species, 32 genera, and 15 families. He also recorded 55 species of mosses for the Pomahuaca-Cajamarca district with 47 genera and 30 families. Opisso and Churchill [7] carried out a study in the surroundings of the Yanachaga-Chemillén National Park in the department of Pasco, in which they indicate the existence of 134 species of bryophytes distributed among 92 genera and 45 families (32 liverworts, 2 hornworts, and 100 mosses).

In the Cusco region, studies on Bryophytes began in 1921 with Fortunato L. Herrera in his work "Flora del Departamento del Cuzco" reporting 26 species of mosses, among which he mentioned *Hygrodicranum herrerai* Williams, *Leptodontium brachyphyllum*,*Tortula affinis* Hampe, *Bryum andicola* Hook, *Ortothrichum elongatum* Taylor, and *Polytrichum antillarum* Rich. Galiano [8] carried out a study on the flora of the high tropical Andean Forest of Yanacocha, in the province of Urubamba, registering 13 species of mosses, belonging to 10 genera and eight families. Tupayachi [9], when evaluating the flora of the Cordillera del Vilcanota, reported 35 species of bryophytes, belonging to 24 genera and 14 families. Galiano et al. [10], when studying the flora of the Cusco Valley, determined 14 species of mosses. Acurio [11] evaluated the diversity and distribution of mosses in the area of Wiñay Wayna, Historic Sanctuary of Machu Picchu-Cusco in an altitude range of 25003100 m, finding 129 species in 72 genera and 29 families. Subsequently, Huallparimachi et al. [12] reported for the Sanctuary 50 species of mosses included in 23 genera and 15 families, highlighting *Bartramia*, *Brachythecium*, *Bryum*, *Campylopus*, *Lepyrodon*, *Neckera*, *Plagiothecium*, *Polytrichum*, *Sematophyllum*, *Sphagnum*,*Tortula*,*Trichostomun*, *Thuidium,* and *Zygodon*.

For its part, Carhuapoma [13] carried out the study of mosses of the Historical Sanctuary of the Pampa de Ayacucho in an altitude range of 3350 to 4100 m, registering 67 species belonging to 45 genera, 21 families, and 11 orders. The Pottiaceae family was the most representative with 10 species, followed by Orthotrichaceae, Brachytheciaceae, and Bartramiaceae with six species each, reporting 23 new records for Ayacucho and the third report for Peru of *Philonotis scabrifolia* (Hook. f. & Wilson) Braithw. expanding its

*Diversity of Epiphytic Mosses (Bryophyta) in Forests of* Polylepis *(Rosaceae) in the Urubamba… DOI: http://dx.doi.org/10.5772/intechopen.108284*

distribution to the south of the country. Despite all these reports, there is still little progress in this division, and it is necessary to encourage these studies and expand our knowledge about the existing bryoflora in Peru and particularly in the Cusco region. The present study is carried out in order to determine the composition of mosses in each of the *Polylepis* forests in the Urubamba Mountain range.
