"Non-vascular" refers to organisms that do not have specialized tissues for transporting water and nutrients. This term is often used to describe certain types of plants, such as mosses and liverworts. These plants absorb water and nutrients directly through their surfaces, which limits their size and the environments in which they can thrive. Unlike vascular plants, which have systems like xylem and phloem to move fluids, non-vascular plants rely on diffusion. This means they typically grow in moist areas where water is readily available. Their simple structure allows them to adapt to various habitats, but they generally do not grow as tall or as large as their vascular counterparts.