Hornworts

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Hornworts

• Anthocerophyta

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Characteristics

• The English word "wort" means "small plant. Thus
  a hornwort is a "small, horned plant".
• Bryophytes
• -non-vascular
• Sporophytes appear to be like horns therefore the
  name hornworts
• Seedless
• Short and nonflowering
• Spore-producing
• smallest of all the 3 bryophytes
• Colonies of photosynthetic cyanobacteria develop
  in cavities of hornworts, giving it a blue-green
  color.
• botanists theorized that hornworts first
  appeared with earliest land plants prior to
  Devonian period

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Genera

• There are six generally accepted genera
• Anthoceros
• Dendroceros
• Folioceros
• Megaceros
• Notothylas
• Phaeoceros

There are over 300 published species names but
it is thought that there are probably only
100-150 species.
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Structures

• Chloroplast-Used for photosynthesis-Contains
  pyrenoids
• Pyrenoids-Carbon-fixating organelles
• -not membrane bound
• Rhizoids-Root-like structure of hornworts
  (gametophyte)
• Foot
• -Keeps the sporophyte attached to the
  gametophyte and also helps in absorbing nutrients
• Thallus-The body of the gametophyte

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Accessory Pigments

• Chlorophylls A and B
• Carotenoids
• Xantophylls

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Reproduction

• alteration of generations
• gametophyte creates plant body (sexual)
• sporophyte produces a spore containing capsule
  (asexual)

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Habitat

• Found globally, usually in moist, shady, and
  sometimes rocky environments
• diverse in tropics
• most abundant in damp places (clay banks)
• most settle in soil or rock
• -some species grow on tree bark
• forests, fields
• ponds, streams, riverbanks

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Nutrition

• Photoautotrophic aerobe plants
• Sporophytes are dependent on the gametophyte for
  nutrients it is parasitic on the gametophyte.

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Ecology

• Primary producers
• Symbiotic relationship with other organisms
  (particularly with the cyanobacteria)
• One of the most popular aquatic plants (can adapt
  to almost any water environment, and can tolerate
  extreme temperatures.)
• Provide habitat for small fishes

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Examples

• Dendroceros giganteusSpecies of hornwort that
  commonly lives on swampy grounds
• Phaeoceros laevis
• commonly found in areas where moisture is
  plentiful, such as moist soils in fields, the
  banks of streams and rivers or inundated beneath
  the surface of the rivers.
• Anthoceros fusiformis
• Also commonly found in moist areas

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Sources

• http//science.jrank.org/pages/1052/Bryophyte.html
  
• http//lifeofplant.blogspot.com/2011/03/hornworts.
  html
• http//kingdomplantae.blogspot.com/2009/02/phylum-
  hornworts.html
• http//www.teara.govt.nz/en/liverworts-and-hornwor
  ts/3
• http//plantphys.info/plant_biology/hornwort.shtml
  
• http//science.jrank.org/pages/1049/Bryophyte-Horn
  worts-division-Anthocerophyta.html