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::: What are seaweeds? Morphology and Taxonomy Reproduction & Life cycles Ecology and distribution Importance and Economic uses Seaweed resources of Taiwan Seaweeds of northeastern Taiwan Search of species of Taiwan seaweeds sitmap Educational activity Game Extension learning Wallpaper
icon Introduction
icon Morphology
  photo Appearance
photo Branching
photo Growth
photo Cell Structure
photo Plastid or Chloroplast
photo Holdfast
photo Asexual Reproduction
photo Sexual Reproduction
icon Taxonomy
  photo Chlorophyta
photo Phaeophyta
photo Rhodophyta
photo Cyanophyta
Search of species of Taiwan seaweeds sitemap Educational activity Game Extension learning Wallpaper
Rhodophyta  Algae in Rhodophyta (red algae) are mostly multicellular. Some are simple uniseriate or multiseriate filaments, others are more delicate and may be branch-like, membranous or foliose. The algal bodies are composed of filaments that can be classified into uniaxial or multiaxial type. Species with uniaxial type have a main central axes which cut off lateral filaments all directions to form a cortex, i.e. the species of the genus Gelidium. The plant bodies with multiaxial type have a number of filaments each terminated by an apical initial, each cutting off a filament to form cortex and medulla, i.e. the species in the order Nemalionales. As cells of red algae often have pit connections, they are the most differentiated and the most beautiful creatures among all algae.

  In addition to chlorophyll a, chlorophyll d, lutein and β-carotene, red algae also contain phycobilins, i.e. phycoerythrin and phycocyanin, so red algae often tend to appear violet red, rose or dark red. Phycoerythrin can absorb blue light, so red algae can grow in deeper ocean waters than other algae. Sometimes, it is possible to find red algae in 200 meters deep. Red algae can be found in all latitudes, but there are usually more red algae in temperate zones and tropic zones rather than in frigid zones. In general, the cell walls of red algae are rich in agar, carrageenan and mucopolysaccharides. They are edible and are used to extract agar and carrageenan. Like brow algae, red algae are utilized in various industries, and they are considered to have more economic value. Some red algae can absorb calcium from seawater and store calcium carbonate in their bodies. These calcarious algae have made great contributions to biological reef building.
  Most red algae have alternation of generations. In their life histories, cells without flagella can not move freely. Their sexual reproduction is oogamy temed carpogonium as the female reproductive cell. The flask-shaped carpogonium has a special trichogyne. Egg cell stays in the matrix. The non-flagellate male reproductive cells termed spermatia have to attach to the trichogyne to fertilize the carpogonium. After fertilization, the nucleus of the zygote will be moved into the supporting or auxiliary cell to grow and produce gonimoblast filaments (= carposporophyte), which will cut off terminal carposporangia. The carposporophyte is parasitic on the female gametophyte. Hence, generally speaking, the life history of most red algae contains three stages, i.e. a diploid sporophyte, a haploid gametophyte and a diploid carposporophyte which is parasitic on the female gametophyte.

  There are 38 families, 114 genus and 261 species of red algae recorded from Taiwan.
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Updated: Jan 30, 2007