SeedPlants213-page7 - they are uncommon in our world today...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Seed-Dispersing Plants - 7 Cycadophyta (The Cycads) There are 9 genera and about 100 species of cycads, including Zamia , which is native to Florida, and a fairly common house plant, Cycas revoluta , the sago palm. Cycads are found in tropical and subtropical regions. They were much more abundant in past eras than today. There is some evidence that seeds require animal dispersal, and that the animals that fed on cycads are no longer around to eat and then disperse seeds. Cycad seeds are difficult to germinate. Cycads are increasingly declining in the "wild" and many are near extinction, both from habitat destruction and because of their slow growth and low reproductive success. Cycads have great value to some as ornamental plantings, so much so that a mature cycad can be sold for several thousand dollars to cycad collectors. That
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: they are uncommon in our world today helps increase their value to collectors, but puts cycads at great risk for poaching from their native habitats, reducing their numbers even more. The safest place today for a cycad is in a botanical garden or preserve. Vegetative Characteristics of the Cycad Sporophytes: Cycads are slow-growing woody shrubs with a short or columnar unbranched stem, up to about 15 meters tall in the largest species. Most are less than 2 meters tall. The stem has a terminal crown of long, leathery, pinnately compound leaves. Cycad leaves have circinnate vernation (like ferns). Some cycads form root associations with nitrogen-fixing Cyanobacteria. The roots that host the Cyanobacteria form at the substrate surface providing light penetration for the Cyanobacteria to photosynthesize....
View Full Document

This note was uploaded on 01/08/2012 for the course BIO 213 taught by Professor Makina during the Fall '09 term at SUNY Stony Brook.

Ask a homework question - tutors are online