Vartika Sharma

Brassica campestris. ( Mustard Family).             Systematic Position:-             Class : Dicotyledonae            Sub class: Polypetalae            Series : Thalamiflorae            Order : Parietales            Family : Brassicaceae Disribution: The family includes 375 genera and 3,200 species widely distributed throughout the world but abundant in north temperate zone with Mediterranean as the major centre.  In India the family is represented by about    51 genera and 138 species mostly in tempreate and alpine Himalayas.  5 elected India genera :- Brassica, Eruca, Capsella, Pvaphanus, Iberis.  Habit : Annual, blennial or perrinial herb with pungent watery sap , herbage commonly covered with branches or stallate unicellular hair , nearly subshrubs.  Vegetative Ch...

                   FOSSILIZATION A fossil in general, may be defined as remains of plants and animals, which lived in remote pass, in many cases,are preserved in the rocks in one form or the other. The study of fossils is known as palaeobotany.  The process of preservation of living beings Or their parts in the form of fossils is known as fossilization. The process of fossilization is a continuing process.  Two theories have been proposed to explain the fossilization process in plants.  1 Replacement theory= According to this theory, fossilization takes place by the replacement of the molecules of the original substances of the plant one by one by the molecules of minerals in soil solution. The replacement occurs due to hydrolysis or weathering of the organic substances present in the plant body. Several known fossils show such type of replacement.  2 Infiltration theory = According to infiltration theory, fossi...