The developmental and physiological traits of rare and threatened moss physcomitrium eurystomum Sendtn. (Funariaceae) valuable for its conservation

Physcomitrium eurystomum Sendtn. is a very rare European ephemeral funaroid moss. The entire European population of this species is considered threatened and it is red-listed in many regions and countries. In addition to being recognized as threatened and included in nature conservation legislation, it also requires active protection measures. This study aims to contribute to effective conservation practices for P. eurystomum. Different conservation physiology tests were carried out to propagate this species to achieve a reliable procedure for biomass production and the potential reintroduction of germplasm. Ex situ tests, both in vitro and ex vitro, were carried out to determine the optimal method for spore production under laboratory conditions, considering that the spores are the best propagules for the reintroduction of the species. An important outcome of this research is a deeper understanding of the role of the spore bank of this species for its survival in a variable environment. Some additional characterizations of the biology of this ephemeral moss species are also discussed, such as the functioning of the photosynthetic apparatus of the vegetative vs. sexual phases to clarify the transition to the reproductive phase. It is proposed that both types of sporophytes be used in conservation practices due to viable spore bank self-sustainability in rapidly changing environmental conditions