I wanted to know about the general classification of plants and here is what I found out: In the field of geography the areas of the world are classified in different ways. One of these ways is to look at the distinctive flora of the different areas of the world, the word flora defining the plant life occurring in a particular region or time, generally the naturally occurring or native plant life. Botanist Ronald D'Oyley Good (1896-1992), a professor of botany at the Hull University, Yorkshire, England, identified 6 floral kingdoms. Building on the work of Prof. Good, Soviet-Armenian botanist Armen Takhtajan (1910-2009), an important figure in 20th century plant evolution, systematics and biogeography, created a system of classification of the following six floral kingdoms:
• Holarctic Kingdom
• Paleotropical Kingdom
• Neotropical Kingdom
• South African Kingdom
• Australian Kingdom
• Antarctic Kingdom
The six floral kingdoms contain a total of 35 regions, with each kingdom having at least one region, and all regions having at least one province, for a total of 152 provinces.
The continent of Antarctica has been too cold and dry to support virtually any vascular plants for millions of years. The cold, lack of sunlight, little rainfall, inferior soil quality and lack of moisture account for scanty vegetation. Plants are not able to absorb water available in the form of ice. Presently the flora of Antarctica consists of some lichens, mosses, liverworts, and numerous terrestrial and aquatic algal species.
“Only two species of flowering plants, Antarctic hair grass (Deschampsia antarctica) and Antarctic pearlwort (Colobanthus quitensis) are found, occurring on the South Orkney Islands, the South Shetland Islands and along the Western Antarctic Peninsula.” (http://www.antarctica.ac.uk/about_antarctica/wildlife/plants/)
Lichens have proliferated in Antarctica because they have a high tolerance of draught and cold. A lichen is a composite organism consisting of a fungus and a photosynthetic partner, growing together in a symbiotic relationship with the photosynthetic partner converting light energy (from the sun) into chemical energy which is later used to fuel the organism’s activities.
I do not think the lichens that live in Antarctica are to be found near any place I live or travel. The lichen the lay person is most familiar with must be the common orange lichen which has wide distribution. It is found in Australia, Africa, Asia, North America and throughout much of Europe. The species was first described by Carl Linnaeus in 1753, as Lichen parietinus. Now labelled Xanthoria parietina, it is a lichen species in the family Telochistaceae. It can be found near the shore on rocks or walls, and also on inland rocks, walls, or tree bark. (the epithet parietina means "on walls").
The upper surface is some shade of yellow, orange, or greenish yellow, while the lower surface is white.
X. parietina is a very pollution-tolerant species. It is also tolerant of heavy metal contamination.
It was chosen as a model organism for genomic sequencing (planned in 2006) by the US Department of Energy Joint Genome Institute (JGI). (http://en.wikipedia.org/wiki/Xanthoria_parietina)
My photographs do not do justice to this versatile plant which is hidden from sight most of the time for the lay person. Also, I realize that I would need botanical and chemical expertise to begin to describe the complex structure of lichens in any adequate manner.