Bryophytes: Mosses and Liverworts



Bryophytes, most commonly represented by mosses have the following characteristics:

  • photosynthetic
  • nonvascular (no xylem or phloem)
  • dominant gametophyte
  • homospory (only one type of spore is produced)
  • swimming sperm cells
  • stay small and close to the ground
  • require moisture for reproduction and growth
  • lack true stems, leaves and roots (they have rhizoids which anchor but absorb little water)

 

They they can be found on soil, rocks, and the bark of trees, and in bogs and shallow streams.

The gametophyte's organs of sexual reproduction, called antheridia and archegonia, contain sperm and egg, respectively

Fertilization can take place only when the plants are wet; after fertilization, the egg grows into a sporophyte.

The sporophyte consists of a base, or foot, embedded in gametophyte tissue; a stalk that is usually long and slender; and a terminal capsule. The capsule, which in most species is covered by a small-toothed lid, contains numerous spores. (see below)