الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 224 |  |  |
| | | from | 224 | | |
Abstract
Plant taxonomy is participated in the detection of variations, examination of their causes and consequences and manipulation of the resulted data to provide a system of classification. Natural classification systems rely on the use of many taxonomic characters and the overall similarities between taxa. It is challengeable to choose these characters carefully and gather them in appropriate quantity to elucidate the relationships among taxa However, the instability of phenotypes, which are easily affected by environmental factors made the classification meet complications (Vogt et al., 2008; Fusco and Minelli, 2010<Haider, 2018).he species rank has specific importance in the classification hierarchy; also it is the standard rank against which others are evaluated. The different species should be isolated by certain barriers to avoid hybridization and gene flow. Even though, the interspecific hybridization is a natural process occurred where the distributions of species overlap. It is an important force in plant evolution and can lead to stabilized introgressant hybrid species Morgan, 2011). These infraspecific ranks as subspecies, variety and form can be numerically and statistically discriminated through morphological characters. Besides, the use of the different genetic markers which can solve the problems concerning the overlapping and indistinct variations, due to their geographical variations, between these controversial taxonomic units (Hardion et al., 2017). However, the infraspecific classification of the wild plants is more problematic due to the large extent of their genetic diversity.