Moss

Mosses are small, non-vascular land plants in the division Bryophyta. They occur worldwide, especially in damp, shaded environments such as forest floors, stream banks, and rock faces. Mosses lack true vascular tissue (xylem and phloem); instead they absorb water and nutrients directly through their leaf-like structures.

The visible part of a moss plant is the gametophyte, a leafy, green thallus that spreads across the substrate. Rhizoids anchor the plant. A separate, dependent sporophyte grows from the gametophyte and consists of a foot, a stalk (seta), and a capsule (sporangium) where spores develop. Mosses reproduce sexually via male (antheridia) and female (archegonia) organs, and most require free water for sperm to swim to an egg. They can also propagate asexually by fragmentation or, in some species, by specialized structures called gemmae.

Life cycle includes alternation of generations with a dominant haploid gametophyte and a diploid sporophyte. Spores germinate to form a protonema, a thread-like filament that later develops into new gametophyte plants.

Ecologically, mosses help stabilize soils, retain moisture, and create microhabitats for small invertebrates and microorganisms. They are pioneer colonizers on bare rock and after disturbance, and they contribute to nutrient cycling. Some species are used in horticulture and for decorative moss gardens; Sphagnum moss (peat moss) is widely used for soil amendment and peat formation.

Mosses are sensitive to environmental changes and are often used as indicators of habitat quality and air/water conditions.