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PHYCOLOGICAL SOCIETY OF AMERICA
Gelidium is a polymorphic genus consisting mainly of highly branched algae with morphological differences in species ranging from from terete (cylindrical) to compressed branches. Different species also show a wide range of sizes from G. pusillum which can be less than 1 cm tall to G. robustum which can reach 40 cm in height. Gelidium species are uniaxial with a dense, central medulla. Growth occurs in Gelidium as the pericentral cells originate through transverse division from the apical cell and form apical cells of lateral branches. This growth pattern results in a morphology described as monopodial branching. Species of Gelidium can vary a lot in color within and between species, from red to purple to green-black.
Specific
anatomical structures are used to identify Gelidium. Small, thick-walled,
wiry rhizoidal filaments are found in the subcortical and outer tissue of
the medulla, and these are thought to function to enhance structual stability.
Cells in Gelidium contain pit plugs, a structure formed from incomplete
division of the cell wall. The layers of material in the pit plugs are used
as a taxonomic characteristic and species of Gelidium have a single
plug cap layer.
Morphology | Life History | Taxonomy | Chemistry | Distribution | Source
© 1999 Sharon C. Komarow. All rights reserved.