Sarvasammalet

Sarvasammalet, or Anthocerotophyta, are a division of bryophytes, a group of non-vascular land plants that also includes mosses and liverworts. They are relatively small and often form flat, thalloid gametophytes that lack true roots, stems, or leaves. The sporophyte develops from the fertilized egg inside a persistent archegonium and typically grows into a horn-shaped structure, which gives the group its common name.

A key biology feature is the horn-shaped sporophyte that remains attached to the gametophyte during its development. The sporophyte surface often bears stomata, enabling gas exchange, while the photosynthetic tissue of hornworts can extend into the sporophyte. The gametophyte interiors commonly contain cavities with symbiotic cyanobacteria, most notably Nostoc, which can fix atmospheric nitrogen for the plant. The chloroplasts in hornwort cells are generally singular and large, often with a distinct pyrenoid.

Ecologically, sarvasammalet inhabit a broad range of moist, shaded environments, including soil, rock surfaces, and sometimes tree bark. They prefer humid conditions and nutrient-poor substrates, and they are often found alongside mosses and liverworts. Globally, there are roughly a hundred or more described species, distributed in temperate and tropical regions.

In science, hornworts are of interest for studies on bryophyte evolution and plant development. Their simple thalloid body plan, unique sporophyte morphology, and symbiotic associations provide insights into early land plant traits and the evolution of plant–microbe interactions.