Catalogue of the vascular epiphytic flora of Uruguay

Abstract

We provide an updated list of the vascular epiphytic flora occurring in native environments of Uruguay based on literature review, herbarium specimens, and fieldwork throughout the country. The catalogue provides standardized information for each species, including accepted name, synonyms used within Uruguay, epiphytic category, distribution within the country, habitat, conservation status, observations, and a voucher citation. The effort documented 73 species for the epiphytic flora of Uruguay (3 % of the flora), distributed among 29 genera and 12 families. Bromeliaceae was the richest family (17), followed by Polypodiaceae (16) and Orchidaceae (12). Tillandsia stood out as the most speciose genus with 15 species. Characteristic holoepiphytes was the most diverse ecological category. More than half of the epiphytic species documented for Uruguay (53 %) reach their southernmost geographic distribution in the country, whereas only two mostly epipetric species of Tillandsia-T. arequitae and T. uruguayensis-are endemic to the country. Almost half of the epiphytic species found are presently under categories of threat of extinction, with 60 % of them occurring in national protected areas. Both the richest epiphytic families and the predominance of characteristic holoepiphytes coincide with findings from floristic and ecological studies previously carried out in humid subtropical regions.

Vascular epiphytes of the Serra do Relógio: the surprising richness of the seasonal forests in the mountains of Minas Gerais, Southeastern Brazil

“…In relation to dispersion syndromes, we found 104 anemochoric species (66%) and 54 zoochoric species (34%) concerning the dispersal syndrome. The high number of Orchidaceae and fern species justifies the predominance of characteristic holoepiphytes, as also found in other studies (Kersten & Silva 2001;Bataghin et al 2010;Barbosa et al 2015;Furtado & Menini Neto 2016;Mai et al 2019). The facultative holoepiphytes are mainly represented by Bromeliaceae, Begoniaceae, and Cactaceae species, while as expected Araceae is responsible for the majority of the hemiepiphytes (Blum et al 2011;Barbosa et al 2019).…”

Accidental epiphytes: Ecological insights and evolutionary implications

“…In contrast, twigs, branches, and stems with bare bark are only rarely occupied by accidental epiphytes, most likely because the majority of the ground‐inhabiting species of moderately moist forests do not tolerate the abiotic conditions in these microhabitats and because it is probably more difficult to attach and establish on these surfaces (Gaxiola et al, 2008; Hoeber et al, 2019). However, in rather dry and open habitats, drought‐tolerant terrestrial species might also occupy canopy sites without abundant bryophytes or arboreal soil (Holmboe, 1914; Mai et al, 2019). The geophyte Hippeastrum morelianum , for instance, occasionally grows as epiphyte with its bulbs entirely exposed on trunks and branches in sun‐exposed outcrops in Southeast Brazil (Alves et al, 2008).…”

“…Host species identity is another factor defining the availability of suitable microhabitats. Tree species differ in crown architecture, the tendency to build cavities, bark surface texture and roughness, bark water‐holding capacity, chemical bark characteristics, foliar density, and litter quality (Cardelús et al, 2009; Cardelús & Chazdon, 2005; González‐Mancebo et al, 2003; Gradstein & Culmsee, 2010; Paillet et al, 2019; Vuidot et al, 2011; Wen‐Zhang et al, 2009), and certain host traits favor accidental epiphytism (Mai et al, 2019). Hence, the availability of suitable substrates and microhabitats for accidental epiphytes differs among host species.…”

“…Undoubtedly, the first obligate epiphytes in an epiphytic lineage must have evolved from terrestrial ancestors in one way or another, and most likely, both scenarios have happened independently of each other in different clades (Benzing, 1989). In any of these evolutionary scenarios, accidental epiphytism constitutes the essential initial stage from a terrestrial toward the epiphytic life form, and empirical support for both scenarios is given, for example, by Mai et al (2019), who observed accidental epiphytes in Uruguay as either being species typically occurring on the forest floor or species from sun-exposed cliffs (mainly bromeliads) eventually reaching nearby trees. Necessarily, these terrestrial species already need to possess dispersal mechanisms that enable them to colonize an arboreal site, and they need to thrive in environmental conditions that are similar to those of an epiphytic microhabitat (Pittendrigh, 1948;Schimper, 1888).…”

Lista comentada de Orchidaceae en Uruguay y su distribución en ambientes y eco-regiones

“…En los últimos años, Izaguirre (2010 y Rossado et al (2014) registran aproximadamente 60 especies en 18 géneros, siendo la mayoría de hábito terrestre y únicamente nueve epífitas. Entre ellas, 12 especies en nueve géneros son indicadas como nuevos registros para el país y Mai et al (2019) publican un catalogo de la flora vascular epífita del país con 12 especies de la familia en siete géneros. En la región, el proyecto La Flora del Cono Sur (2020) menciona 132 géneros para el Cono Sur; mientras que Andrade et al (2018) reportaron 149 especies en 54 géneros de Orchidaceae en los pastizales del Río de la Plata de la región Uruguayense (incluye Uruguay en su totalidad, el Sur de Río Grande del Sur de Brasil y el Este de la provincia de Entre Ríos en Argentina) de los cuales 19 géneros con 57 especies pertenecen a Uruguay.…”