During the past few deades biologists have been trying to calssify living organisms into various groups which could logically reflect their similarities and dissimilarities at various levels. The groups were supposed to foreshadow the natural relationships among living organisms and their mode of origin. Such a system of classification is called Phylogenetic System of Classification.
Kingdom plantae mainly includes eukaryotic, autotrophic, multicellular, non motile organisms which develop from embryos. Plant cells have cell wall outer to cell membrane which is composed of cellulose. There are about 360,000 known species of plants.
Classification of Plantae
For the sake of convenience organisms included in Plantae can be divided into two broad categories viz. non vascular (Bryophyta) and vascular (Tracheophyta) plants. Although this grouping is not according to any specific system of classification but it does reflect similarities and dissimilarities among various groups of plants. Each category (division) is divided into Sub-divisions, Classes, Sub-classes and other taxonomic ranks. Detailed discussion of classification of Plantae will be beyond the scope of this book. Following is a brief outline of classification of plantae.
Table 9.1: An outline of Classification of Plantae.
|Divison: Bryphyta – (Non-Vascular Plants) Common Name
Sub Division Hepaticopsida Liverworts
Sub Division Musci (Bryopsida) Mosses
Sub Division Anthoceropsida Hornworts
|Division : Tracheophyta – (Vascular Plants)
Sub Division Psilopsida Whisk ferns
Sub Division Lycopsida Club mosses
Sub Division Sphenopsida Horse tails
Sub Division Pteropsida Fern seed plants
Class Filicineae Ferns
Class Gymnospermae Naked-seeded plants
Class Angiospermae Flowering Plants