Order: Cycadales; Families: Cycadaceae, Zamiaceae, Strangeriaceae
225 million years ago in the Jurassic Period when dinosaurs roamed the swamps of Pangaea, the era of cycads arrived. They were the first cone-bearing seed plants to appear, along with ginkgos and conifers. Called “cykos,” Greek for “palm-like,” cycads resembled palms with their frond-like pinnate leaves. Unlike palms, their trunks contained tissues of woody xylem found in trees.
There are about one hundred species of living cycads: Sego Palms, Pineapple Palms, Giant Dioons, are all called cycads though in different genera, differing from each other principally by leaf venation. Their stubby golden trunks are rough with the bases of broken-off fronds. Their fern-like leaves occur in a cluster at the top of the trunk, and the reproductive cone structures appear at the end of branch-like stalks. Some species have cones 3 feet long, weighing 90 pounds! Their roots have a symbiotic relationship with blue-algae, assimilating nitrogen from the atmosphere.
Cycads are dioecious: male cones containing pollen grow on one plant, female cones on the other. Like conifers, wind is their pollinating agent. Cycads appear in tropical and sub-tropical areas of Australia, Mexico and Africa; some are at home in wet forests, others thrive in semi-arid areas. They can make ornamental if slow growing houseplants.
||Cycadaceae, Stangeriaceae, Zamiaceae.
Genera (at SFBG): Cycas, Bowenia, Zamia, Encephalartos, Macrozamia, Lepidozamia, Dioon
||Five basic items are needed for cycad growing success: well-drained soil, warmth, sufficent light, sufficient water, and fertilization
||New leaf grow occurs seasonally. Male and Female cones usally takes place seasonally as well, but can alternate years with the new leaf growth
||Can be grown quite well in pots as the roots are exposed to higher temperatures. As with most plants, putting a cycad in the ground is the best way to achive healthy results, besides looking splendid, they give bay area yards a real tropical look. Be sure to have the five bases covered as mentioned above and you will have many years of Cycad enjoyment.
||All Cycads are endangered and are regulated by the Convention on the International Trade of Endangered Species of Fauna and Flora (CITES)
Cycads are considered superior to palms by some as they are slower growing and therefore do not outgrow their landscape.
Sex reversal has been reported to occur in Cycads; it is very rare but usually occurs due to extreme trauma or stress
The Cycad Society is a nonprofit organization dedicated to education, research and conservation of cycads. They also produce a quarterly newsletter that is packed full of great stories and resources.
Cycads can be found in the Ancient Plant Garden (Beds 68a, 68b, 68c) and the South Africa Garden (Beds 27 and 44).
IN BLOOM CONTRIBUTORS:
Docents Joanne Taylor and Kathy McNeil
Profile Contributor: David Kruse-Pickler, Associate Curator