Attemps to Classify

In this chapter, we will describe Plantae kingdom under Algae, Bryophytes, Pteridophytes, Gymnosperms and Angiosperms. At present phylogenetic classification systems based on evolutionary relationships between the various organisms are acceptable.This assumes that organisms belonging to the same taxa have a common ancestor.

• Plant classification is arrangement of plants into groups and subgroups on the basis of their functions and characters.
• In a majority of systems which recognized only two Kingdoms of organisms, the plants were included in the Plant Kingdom and animals were placed in the Animal Kingdom.

Artificial System of Classification:

• Aristotle and other Greek philosophers divided living organisms into two groups, plants and animals. Aristotle also divided plants into 3 groups; herbs, shrubs and trees. He also divided animals into two groups, one having red blood (Enaima) and the others without red blood (Anaima). Charaka (the father of Ayurveda), book Charak Samhita.
• Carolus  Linnaeus  has given the Sexual System of Classification

Natural system of Classification

Several  systems of classification of plants were proposed by taxonomists. Out of these, the common system was proposed by Schimper  and Eichler etc.

• About 90% of the total species grow in fresh water habitats and 10% are marine. They are cosmopolitan in distribution.
• Asexual reproduction takes place by mitospores. The common asexual spores are zoospores , etc.
• Sexual reproduction is by isogamy, anisogamy and oogamy