Silva, Paul C. Department of Botany, University of California, Berkeley, California.
Moe, Richard L. Department of Botany, University of California, Berkeley, California.
- Additional Readings
An order of green algae (Chlorophyceae) in which the plant body (thallus) is composed of a nonseptate axis, attached by rhizoids and bearing whorls of branches. The walls utilize a partially crystalline mannan (polymer of mannose) as the skeletal component and usually are impregnated with aragonite, a form of calcium carbonate, causing these algae to be easily fossilized. Among green algae, only the Dasycladales have a fossil record sufficient to permit meaningful phylogenetic speculation. About 140 extinct genera have been described (Fig. 1) from limestones as old as the Ordovician, with three peaks of abundance and diversity—Carboniferous, Jurassic-Cretaceous, and Eocene. Only about 11 genera comprising 50 species are extant, with 3 of the genera extending from the Cretaceous. All are confined to warm marine waters except Batophora, which occurs as a relict in brackish sinkholes in New Mexico in addition to having a normal Caribbean distribution.
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Contributors include more than 9000 highly qualified scientists and 43 Nobel Prize winners.
MORE THAN 8700 articles covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 19,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information