Format: ORAL

Ricardo Garilleti1, Isabel Draper2,3, Juan A. Calleja2,3 Francisco Lara2,3

1. Departamento de Botánica y Geología, Universidad de Valencia, Spain. 2. Departamento de Biología, Universidad Autónoma de Madrid, Spain. 3. Centro de Investigación en Biodiversidad y Cambio Global, Universidad Autónoma de Madrid, Spain.

The subfamily Orthotrichoideae, comprising 14 genera and approximately 360 species, plays a significant role in epiphytic communities within temperate regions and high tropical mountains worldwide. Four genera notably contribute to the subfamilys diversity, accounting for around 94% of its species: Orthotrichum (ca. 110 taxa), Zygodon (80), Lewinskya (75), and Ulota (70). The latter genus boasts a subcosmopolitan distribution but stands out for its greatest diversity in the hyper-humid oceanic-temperate climates of the southern hemisphere. In western Patagonia, thriving within these conditions, Valdivian temperate forests and Magellanic subpolar forests host 23 recognized Ulota species so far. All these species are endemic to the area, exhibiting remarkable and rare dispersion-related adaptation patterns that could have emerged during radiative processes. Many species show adaptations that limit spore release, such as oversized endostome segments or capsule mouth contraction. Moreover, large spores are very common, and among Patagonian Ulotae the abundance of spores with endogenous germination (multicellular spores) stands out. Despite being an uncommon feature in the genus, this trait has appeared in up to six species in Patagonia. Large and heavy spores as those found here might face challenging long-distance dispersal. Arguably, both climatic preferences and dispersal limitations could be linked to an evolutionary pressure for spores to remain within favorable locations, particularly in this territory where strong winds can transport propagules to adverse environments, including the nearby ocean. In addition, rapid germination significantly aids the establishment of new individuals in similar and suitable conditions. These adaptations, whether occurring as syndromes or in isolation, are also observed in other regions, such as Australasia, China, or Japan. Current data suggest that this intercontinental pattern might reflect parallel evolution that arises from homoplasy, which is common in the family.