Non-vascular plants are plants without a vascular system (xylem and phloem). Although non-vascular plants lack these particular tissues, many possess simpler tissues that are specialized for internal transport of water.
Non-vascular plants do not have a wide variety of specialized tissue types. Leafy liverworts have structures that look like leaves, but are not true leaves because they are single sheets of cells with no cuticle, stomata or internal air spaces and have no xylem or phloem. Consequently they are unable to control water loss from their tissues and are said to be poikilohydric.
All land plants have a life cycle with an alternation of generations between a diploid sporophyte and a haploid gametophyte, but in all non-vascular land plants the gametophyte generation is dominant. In these plants, the sporophytes grow from and are dependent on gametophytes for taking in water and mineral nutrients and for provision of photosynthate, the products of photosynthesis.