In bryophytes, establishment can occur by a sexual or asexual process, but the production of spores enables colonization of a wider range of habitats and substrates than can asexual propagules. Successful germination is critical for establishment in a new environment. Th is paper addresses germination and sporeling development in Frullania ericoides, a leafy liverwort species. Fresh spores were inoculated in vitro in diff erent culture strengths of Knop's nutrient solution (one-fourth strength, half strength, full strength, one and a half strength and double strength), in order to evaluate the eff ects of this solution on spore germination and on the development of external protonema. On the fi rst assessment, spore germination was observed at all the concentrations. Germination was endosporic, with cell division and proliferation, resulting in a globular protonema, within the spore wall. Beginning at the fourth week, the development of tightly concave primordial leaves was observed in all but the double-strength medium. Th roughout the period of study, the treatments with lower concentrations exhibited external protonema with greater lengths. Th e double-strength treatment was statistically diff erent from other treatments in at least two parameters. Th e results of this study demonstrate the potential of in vitro culture techniques for bryophyte spore studies and germplasm preservation.