18/02/2023
Lichen is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship. Lichens have properties different from those of their component organisms. They come in many colors, sizes, and forms and are sometimes plant-like, but are not plants. They may have tiny, leafless branches (fruticose); flat leaf-like structures (foliose); grow crust-like, adhering tightly to a surface (substrate) like a thick coat of paint (crustose); have a powder-like appearance (leprose); or other growth forms. They show obligatory mutual relationship where absence of one will lead to the extinction of the other.
Growth Forms
There are three main types of lichens:
1) Foliose
2) Fruticose
3) Crustose
Foliose lichens have two easily distinguishable sides. In other words, there is a top side and there is a bottom side. They can be very flat, leafy like lettuce, or convoluted and full of ridges and bumps.
Fruticose lichens can be pendant and hair-like, upright and shrubby, or upright and cup-like. Many fruticose lichens have round branches that have a central core and others are hollow in the middle. Other fruticose lichens have flat branches that tangle up with each other.
Crustose lichens are just that, crusts. They form a crust over a surface, like a boulder, the soil, a car, or your roof shingles. They can come in many bright, vibrant colors like sunny yellow, orange, and red, as well as grays and greens. Crustose lichens are pressed against their substrate.
Reproduction :-
Can you imagine how two different species living in the same body reproduce? We know that to reproduce, we need to have two of the same species to produce fertile offspring. Lichens are unique in that they are composed of two (or more) different species, or in fact, kingdoms.
Lichens are different. Unlike plants that can produce seeds that grow into new plants, lichens do not have a straightforward way to grow more lichen. Since the fungus is the dominant partner in the relationship, it gets to develop its fruiting bodies and produce spores. These spores can produce another fungus, but unfortunately, for the algae, it does not get the opportunity to reproduce at all. Either the new fungus has to find an algal partner or it perishes.Of course, evolution must go on, and lichens have adapted to their bi-specific struggle. These organisms can vegetatively reproduce; that is, they have structures specifically developed for the spread of fragments of their thalli, with both partners. Not only are there specific vegetative structures, but simple fragments of lichen can grow into full-size thalli.
03/09/2022
23/03/2022
19/01/2022