Eckenwalder, James E. Department of Botany, University of Toronto, Toronto, Ontario, Canada.
- Additional Readings
A class of the division Cycadophyta consisting of a single order, Cycadales, dating back to the Triassic and most abundant in the Jurassic. There are 100–150 living species of cycads in two families, Cycadaceae with one genus and Zamiaceae with ten genera. Most cycads are tropical, but some extend into warm temperate regions. Wild cycads are threatened by collection for horticulture so are protected by international treaties. They were used as traditional foods in some places but contain potent carcinogens and neurotoxins. See also: Cycadales; Gnetales; Welwitschiales
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