Phylum Bryophyta

• Especially common in moist terrestrial  places
• No vascular tissue
• Gametophytes are dominant & photosynthetic
• Homosporous
• External water is necessary for fertilization
• Seed less plants
• Do not bear flowers
• e.g; Marchantia, Mosses- Pogonatum

Bryophytes are called amphibians of the plant kingdom because these plants though live in soil but they need water for sexual reproduction.

• • The sperm of bryophyte (antherozoids) are flagellate and need water to swim to the eggs.
  • None of the bryophytes are found in aquatic environment
  • Have a special type of conducting system
  • Sporophytes are parasites which totally depend on gametophyte
  • Produce biflagellated spermatozoid
  • Show heteromorphic alternation of generaion

   

  • Marchantia
  • Flattened shape
  • Grow parallel to the earth surface
  • Yellowish green colour
  • Thallus structure formed dorso – ventral
  • Possess hexagonal arrangement on the dorsal surface
  • In the middle of each hexagon there exist microscopic aero pores
  • Known as liverworts
  • Mid rib is found in the thallus
  • Several gemma which involve in the asexual reproduction are found on the surface of thallus
  • Rhizoids are found on the ventral surface
  • Unisexual , dioecious
  • In the tip of the thallus archegonia and antheridia could be seen which are attached to the thallus by stalk

   

  • Poganatum
  • Found in shady moist surface
  • Possess pseudo leaf, pseudo stem and rhizoid
  • Grow perpendicular to the earth surface
  • Microscopic
  • Greenish colour
  • Unisexual, dioecious

   

  Features of Bryophyte which make it unsuitable for terrestrial environment

  • Cuticle absent
  • Do not possess true root system and well developed conducting system (xylem and phloem)
  • Supporting tissues are not developed
  • External water is necessary for fertilization