Rhytidiadelphus

Rhytidiadelphus is a genus of mosses belonging to the family Hylocomiaceae. These mosses are typically found in temperate and boreal regions of the Northern Hemisphere, often growing in moist, shaded environments such as forests, bogs, and along stream banks. They are commonly encountered on the ground, on decaying wood, or on rocks.

Species within Rhytidiadelphus are characterized by their creeping or procumbent stems that can be quite long, often forming loose mats or tufts. The leaves are typically ovate to lanceolate and possess a plicate or folded appearance, which gives the genus its name (from Greek "rhytis" meaning wrinkle). The leaves are often toothed along the margin and may have a prominent costa, or midrib. Sporophytes, when present, consist of a capsule that is usually inclined and borne on a seta.

A well-known species is Rhytidiadelphus triquetrus, often called the "rough-leaved bryum" or "triquetrous moss." This species is widespread and can form extensive carpets in coniferous forests. Another common species is Rhytidiadelphus squarrosus, known as "square-shouldered moss" or "springy moss," which frequently colonizes lawns and other disturbed grassy areas. The genus plays a role in soil stabilization and moisture retention in its habitats. Identification of species often relies on microscopic examination of leaf shape, cell structure, and the characteristics of the sporophyte.