BRYOPHYTES (23.3) Tasha Fisher and Emily Crawford

What are Bryophytes? Archidium ohioense, a moss  Include the mosses, liverworts, and hornworts.  Are the simplest of plants.  About 20,000 species  Found throughout the world, but are prevalent in moist and shady areas  can be found in alpine regions, where they are subjected to freezing, and some in deserts, where they are desiccated most of the time  Many are highly specialized, and found in restricted habitats

Unique Characteristics Gottschelia schizopleura, a liverwort  Lack vascular tissue  must absorb all water and nutrients at the surface and pass them from cell to cell.  few have modified water transport cells called hydroids, and a few have solute conducting cells, called leptoids, but this is rare.  leaves are not true leaves because most species lack vascular tissue.  Leaves are functionally equivalent to “real leaves” because they contain chlorophylls a and b.  “Leaves” are usually one-cell thick, except for the midrib, which may be up to 15 cells thick.  satisfy their nutritional requirements by absorbing minerals from dust, rainfall, and water running over their surface. Lack of Vascular Tissue

Unique Characteristics Phaeoceros oreganus, a hornwort  Bryophytes are small and the tallest are 20 cm in height while the shortest are about 2 cm in height.  Often grow in prostrate masses or clumps because they don’t have any vascular tissues needed for upright growth.  They do not have roots therefore they attach to the soil with rhizoids.  Most of them are soft and pliable.

Unique Characteristics Barbula indica, a moss  Survive best in moist habitats but many can tolerate dry areas by lowering metabolic needs. Also known as desiccating  All mosses, liverworts, and hornworts have three traits that they share and that evolved in early plants: a waxy cuticle, cellular jacket, and large gametophytes.  If they dry out, they can simply be revived by water.

Uses of Bryophytes Japanese Moss Garden  Mosses are used in gardening, agriculture, medicine, and the construction of homes.  Other uses for mosses are all-natural insect repellants, boot liners, and fuel.  Liverworts are sometimes used for medicinal purposes.  They also very useful in determining any environmental changes.

Life Cycle of Bryophytes  Varies among the three divisions  In General…. Sperm is released from the antheridium and uses water to reach the egg in the archeogonium. A zygote forms and undergoes mitotic division until it develops into an embryo. Embryo grows until it becomes a sporophyte in which spores form. The spores are then released and germinate. The spores will form either male or female gametophytes.

Life Cycle of Moss