Ferns

There are more than 10,000 described species in the world.

New Zealand has around 200 species and about 80 of these are endemic (found nowhere else). 

There are two major groups of ferns, those with a large, passive sporangium (eusporangiate ferns) and those with a small sporangium that actively disperses the spores (leptosporangiate ferns).

• except for tree ferns, the stem is creeping (rhizome); all stems contain conducting tissue
• most leaves are large (megaphylls) with forked venation and are called fronds; these are often dissected into leaflets
• young fronds are coiled into croizers or fiddleheads
• sporangia are found on the underside of fronds
• in the whisk and fork ferns roots are lacking and the stem is attached to the substrate by filamentous rhizoids 
  
• in the whisk and fork ferns sporangia are borne on the upper suface of forked leaves

Ferns can be traced back almost 400 million years to the Lower Devonian period and became very abundant 360 million years ago in the Carboniferous period.