Basket Fern	Beautiful Fern	Birds Nest Fern	Bowenia Fern
Scaly Tree Fern	Ribbon Fern	Elkhorn Fern	Staghorn Fern
Hare's foot Fern	King Fern	Maidenhair Fern	Coral Fern
Fork Fern	Electric Fern	Tassel Fern	Pronephrium asperum
Spleenwort Fern	Giant Brake Fern	Cyathea rebeccae	Amphineuron opulentum
Tectaria muelleri	Bat-Wing Fern	Diplazium dilatum	Potato Fern
Brake Fern

FERN FACTS!

• Worldwide there are over 12,000 species of ferns.

• The Wet Tropics is home to 65% of Australia's fern species.

• In Australia there are 390 native species of ferns, 47 species of fern allies, 44 species of conifers and 39 of them are endemic.

• Forty fern species are endemic to the Wet Tropics.
   

Epiphytic Ferns

• Epiphytic ferns are one of the most common features in rainforests.

• They grow on the trunks and limbs of trees but unlike parasitic plants such as mistletoe, do not steal nutrients from their host tree.

• They survive instead on rainwater and the nutrients they get from trapped fallen leaves.

• Visitors often mistake them for bird’s nests, tree parasites, or part of the tree.

• It is not uncommon to see a large number of both species and individuals on the one tree. 

• Many can grow to a size where they are larger in diameter than the tree that supports them.

• Sometimes the host tree taps into the fern though. Roots have been found growing from the host tree into the epiphytes.

The Evolution of Ferns

• In the evolutionary development of plants, ferns represent a great advance on all previous models. The surface cells of aquatic algae are able to absorb nutrients and water, on land it is necessary to divide up the tasks, a step which makes the plants more adaptable.

Roots:

• Roots were a revolutionary new feature dedicated to seeking out less accessible sources of water, thus allowing plants to move inland. 
• They also served to stabilise the larger models.
• Water and nutrients, taken up by the roots, had to reach other parts of the plant so a plumbing system - the vascular system -evolved. 

Xylem:

• Woody vessels (xylem) performed this function, moving water and nutrients upwards. 
• These vessels had a duel function, providing rigidity to the tissues. 
• With these load-bearing structures the plants were able to grow much taller and reach up to the light.

Phloem:

• Another plumbing system was needed to move the sugars and other photosynthetic products from the leaves to the rest of the plant. 
• This function was performed by another new system of vessels, the phloem.

Leaves and Photosynthesis:

• Leaves were another fern invention - a system of solar panels dedicated to capturing the energy of the sun and turning it into food. 
• Exposed to the air, these had to be sealed to prevent the water gathered by the roots from leaking away so a waxy skin (cuticle) was developed. 
• Since the process of photosynthesis requires an intake of carbon dioxide from the atmosphere and waste oxygen must be released, special design features in the cuticle - pores - allowed this exchange of gases to continue.

Other Early Vascular Plants:

• Although ferns were among the earliest vascular plants (algae, lichens, mosses and liverworts are all classified as non-vascular plants) they were not the only ones.
• The fossil records tell us that at one time the world was dominated by massive clubmosses, giant horsetails and others which created magnificent forests 45m or more in height as they used their newly developed vascular systems to reach higher and higher in competition for sunlight.
• Many of these plants are now extinct, their relatives hanging on comparative obscurity.

                Sexual links with the past

• Although ferns are structurally more advanced than mosses, like the more primitive algae and mosses their sex life involves two generations and a dependence on water.

• Spores are produced by the fern plant in spore cases, usually beneath the leaf.

• When released, each spore grows into a tiny heart-shaped structure known as the thallus which, in turn, produces male sperm cells at the pointed end and female cells in the notch.

• In the presence of water, the sperm burst free from the thallus and, attracted by chemicals, swim to the female cells.

• Following fertilisation, an adult plant develops, eventually dwarfing its `parent' thallus. 

• Curiously this large spore-producing fern plant is the equivalent of just the tiny spore capsule and stalk of the moss plant while the much more obvious green moss plant is the equivalent of the tiny fern thallus. 

• Both produce sex cells.

• Many ferns can, of course, increase their numbers asexually by spreading their rhizomes-stems which are either below the soil surface or just above it. 

• Roots grow down from the rhizomes while fronds sprout from the top.
  
  Courtesy of: Environmental Protection Agency, Cairns.
  
   

• While many of the plants in the rainforest have been around for millions of years, ferns have been around for much longer than that! They appeared in the fossil record dating back to 325 million years ago.
• They are one of the earliest vascular plant forms on the planet (plants which circulate water internally) and they preceded the flowering plants, the conifers and even the cycads - all of which have a more advanced means of reproduction.
  
  Additional Information: Courtesy of Damon Ramsey
   

Fern allies

• These plants have a long fossil record, and are usually thought of as the most primitive of all vascular plants.

• They differ from ferns by lacking the large leaf-like fronds, and the spore containing sporangia are found on the terminal ends of the leaf rather than on the underside as in most fern species (Jackes and Cairns 2001).

• Back in the Carboniferous period, even before the dinosaurs, some species in these groups grew as large as trees, and often comprised the dominant vegetation.

• Today they are found all over the world, but only as small obscure species.

Cycads

• Cycads were one of the dominant plant forms back in the Mesozoic, the 'Age of the Dinosaurs', when they would have comprised much of the forest as flowering trees do today.

• Many species of cycads are toxic, containing the lethal compound macrozamin (including the species found in the rainforests here), and it has even been suggested that this high toxicity initially evolved in this ancient group to deter predation by dinosaurs.

• However in the present day cycads are fairly restricted and less than a few hundred species survive in the tropics and subtropics of the world.

• Cycads usually have a trunk with the new leaves coming out only from the top, and thus superficially resemble palm trees.

• Howevor they are not true flowering plants, but gymnosperms, and reproduce with cone-like structures.
  
  Script: Courtesy of  Damon Ramsey BSc.(Zool) Biologist Guide