It is believed that ferns are some of the oldest plants in the world, and a staggering number of 10,560 species of fern are known at the moment. These plants are members of vascular plants group that reproduce via spores. Tree ferns can grow big - up to 25 meters (or 82ft) in height. One of the more interesting facts about ferns is that people during the Victorian times were absolutely obsessed with them. These plants appeared in pottery, wood, metal, textiles, printed paper and sculptures and the obsession has even got its name - a Fern-Fever or Pteridomania.