Moss, one of the earliest of Earth’s land plants, is part of the bryophyte family. Despite appearances, moss actually does have roots, stems, and tiny leaves, more properly called microphylls, which is where photosynthesis occurs.
Moss is a non-vascular plant, meaning that it has no internal system to transport water. Instead, it grows by spreading out as ground cover and usually reaches less than 8 inches in height.
Photosynthesis is the process by which plants make and store their food. With the help of a green substance called chlorophyll, the heat of the sun is combined with carbon dioxide and water and converted to sugar and starch. The process releases oxygen as a waste product.
Rather than true leaves, mosses have microphylls. These leaf-like structures with a single unbranched vein evolved from tiny bits of tissue found on the stems of leafless, more primitive plant forms.
The gametophyte is the dominant phase in the life cycle of moss plants. This is the form of the plant most people are familiar with since it is often seen carpeting trees, rocks, and parts of the forest floor. Photosynthesis takes place in the gametophyte phase.
Moss reproduces by the creation of spores held within sporophytes. These sporophytes have no photosynthetic capabilities, so they are dependent on the gametophytes for nutrition needs.