Monterey Bay Aquarium Research Institute
Marine Botany

coralline drawing and title

       The articulated corallines constitute a diverse group of branched, calcified red algae. Found in nearly all of the world's marine habitats, articulates primarily occupy intertidal and subtidal coastal areas. Spotting these algae in even deeper waters is not uncommon though. Their characteristic branching and calcium carbonate cell walls make them difficult to miss.

       Most articulates grow as individual plants on rocks or granular substrates. However, some of these algae can grow as epiphytes, growing on the shells of benthic marine organisms or other algae. Corallines often grow bunched together in clusters but some species are distributed more sparsely.


Corallina is just one example of an articulated coralline.

       All corallines share common characteristics, including calcification, reproduction in conceptacles, and filamentous organization. The primary characteristic that separates the articulates from their crustrose brethren is the presence of flexible, uncalcified joints called genicula. These joints give the articulates the flexibility needed to withstand the fierce and volatile motions that come with life in the oceans.

       Even though the subfamilies of articulates have many similarities, they also have bear some striking differences. The most notable features that distinguish groups of geniculates from each other are branching patterns and thickness, location of reproductive organs, and cell organization within tissues. Sometimes it is impossible to differentiate amongst species without sectioning samples and looking at them under a microscope.

corallines at 90 feet deep

A colony of articulated corallines found ninety feet deep in the Monterey Bay.

       I hope this site presents a clear and interesting portrait of the articulates. They are a most fascinating group of organisms. Below are links to broad categories within which information is organized into specific topics. Links back to these broad topics can be found at the bottom of each page. Please enjoy.

Evolution  |  Ecology  |  Systematics  |  Mechanics  | Pigmentation  | Morphology  |  Reproduction  |  Life History References  |  Procedures    Acknowledgements  |  Main  

© 2001 Ian Ehrenreich. All rights reserved.