Prehistoric period divided into: era, period and epoch. The record is given on the basis of: Data derived on the basis of character of the earth’s strata and the fossils that they contain. Fossils of some pteridophytes & gymnosperms. Distribution of gymnosperm plants in prehistoric times. Overall distribution of plant …

Biodiversity is the outcome of evolutionary and ecological processes. Biodiversity causes biodiversity. Environmental factors have significant effect on genetic diversity. Evolution is the center of genetic processes. New spp. via micro-evolution or destruction via macro evolution or diversity via mutation. Factors for Biodiversity Creation (A) Primary factor (B) Ecological Templates …

Systematic position According to Bentham and Hooker it is placed under the series Coronaricae. Engler places it under the order Liliflorae. Hutchinson places it under the order Liliales of the division Corolliferae. Distribution The members of the family are cosmopolitan and specially abundant in the warmer parts of the tropical …

Systematic position Bentham and Hooker placed it in the sub-class Gamopetalae, the series Bicarpellate and Cohort Gentianales. According to Engler, it belongs to the sub-class Metachlamydeae, the sub-order Tubiflorae, the sub-order Verbenineae. Hutchinson places it under the order Lamiales belonging to the phylum Herbaceae. Distribution The family contains about 200 …

Systematic position Bentham and Hooker placed it in the sub-class Gamopetalae,the series Bicarpellate and Cohort Gentianales . According to Engler it belongs to the sub-class Metachlymadeae, the sub-order Gentianineae under the order Controtae.Hutchinson places it under the order Apocynales of the Phylum Lignosae. Distribution The family contains about 300 genera …

Systematic position According to Bentham and Hooker it belongs to the series Microspermae. Engler places it under the order Microspermae.Hutchinson considers it as belonging to the order Orchidales of the divison Corolliferae. Distribution The family is large and is consisting of over 400 genera and more than 10,ooo species distributed …

Systematic position Bentham and Hooker places this family under the series Glumaceae of the Monocotyledons. According to the Engler it belongs to the order Glumiflorae. Hutchinson places it under the order Graminales belonging to the division Glumiflorae. Distribution The members of this family is cosmopolitan and grow on almost all …