A lot of research has been done showing that biological nitrogen fixation occurs inside the roots of vascular plants via the rhizophagy cycle. Although such research in higher plants has been instrumental to understanding the function of biological nitrogen fixation, similar research in bryophyte symbiosis remains inconclusive. The bryophyte clade is older than seed plants and might reflect more ancestral associations and symbiotic relationships between plants and bacteria. Bryophytes have been associated with  nitrogen-fixing bacteria in nitrogen-cycling studies, but the specific mechanism of how bacteria are providing nitrogen to the bryophyte cells is unknown. We utilized new staining methods and freshly collected materials of several mosses and liverworts to get a better understanding of the cellular activities of bryophytes and the bacteria incorporated in some of their cells. Different chemical stains were used on specimens under microscopic magnification and often showed bacterial endosymbionts moving inside the bryophyte's rhizoids in the apices of immature filaments, as well as in other non-photosynthetic structures. The goal of this project is to get a better understanding of the mechanisms through which these bacteria obtain nitrogen from the air, their function and development, and the patterns associated with how nitrogen is acquired and moves inside the bryophyte cells. A close association between bryophytes and nitrogen-fixing bacteria is hypothesized to be beneficial to bryophyte growth and survival. Such mutualism, or potential ‘plant farming’, where the moss uses bacteria to produce nitrogen inside its cell, could indicate early species-interactive relationships in land plant lineages from over 400 million years ago.