Ferns

These plants have big leaves, called fronds, they do not produce seeds and they generally need water to fertilize. For this reason they are generally found in humid and shady forests and in marshes.
On the underside  of  sporophyte leaves,  circular shaped organs called sori, containing  spores, can easily be seen . They  can  be of the same size or of different sizes (microspores and macrospores) and  when they germinate they can give rise to different gametophytes (male and female gametophytes). They often generate a single type of gametophyte,  a few centimetres in size, which grows on contact with water. Gametophytes are often heart-shaped and have only one layer of cells containing chlorophyll. Archegonia and antheridia are located in separate areas and they surround the gametes. The antheridia contain a large number of multiflagellated sperm, and if there is sufficient humidity, they spill out and make their way, by chemotropism, towards the archegonia. In the beginning the young embryo  feeds on the gametophyte, which in turn degenerates. Some ferns  grow up to 20 metres in height, and stand tall like trees.

 

Special reports

  • 26 October 2022

    Praising the meatball

    Let's learn to transform waste into resources!

    10 October 2022

    Spider lullaby

    There are spiders that weave a classic web, that one we all know, to catch prey. There are others who…

  • 19 September 2022

    Double blow to dinosaurs

    The Main Asteroid Belt is between Mars and Jupiter, an enormous ring consisting of millions of large and small rocks…

    24 May 2022

    Amphibians in peril

    The International Union for Conservation of Nature (IUCN) warns: the extinction rate of amphibians is about 200 times greater than…

  • 8 March 2022

    8 March. We remember Rosalind Franklin, the great female DNA scientist.

    DNA was first isolated by Friedrich Miescher, a Swiss biochemist in 1869. It was a brilliant, but not complicated operation:…

    27 February 2022

    In search of the riders of icebergs

    International Polar Bear Day, set up by Polar Bears International, a non-profit organisation, was held on 27 February. The aim…

  • 26 October 2022

    Praising the meatball

    Let's learn to transform waste into resources!

  • 10 October 2022

    Spider lullaby

    There are spiders that weave a classic web, that one we all know, to catch prey. There are others who…

  • 19 September 2022

    Double blow to dinosaurs

    The Main Asteroid Belt is between Mars and Jupiter, an enormous ring consisting of millions of large and small rocks…

From the Multimedia section

  • life

    Photosynthesis in action

    Look
  • life

    Detecting vitamin C

    Look
  • life

    Detecting starch

    Look

Facts