Biosystematic studies on Brassicaceae (Cruciferae) in Egypt

<font size="2">The present work deals with a systematic investigation of 45 taxa belonging to 23 genera of the tribes Arabideae, Euclidieae, Hesperideae, Lunarieae, Matthioleae and Sisymbrieae of the family Brassicaceae from Egypt. This work is largely based on herbarium material received on loan from B, BM, BR, E, HUJ, K, KSU, L, LY, NMGM, OXF & FHO and W, and collections kept in the following herbaria; B, CAI, CAIM, WAG and Sohag University Herbarium (SHG, proposed abbreviation). In addition, fresh material of most of the taxa was studied and field observations were made from several localities in Egypt.<strong>Chapter 1</strong> describes the family as a whole, presenting a historical review, its phytogeography, uses and economic importance, an outline of the thesis, aims and general objectives.<strong>Chapter 2</strong> deals with the materials and methods used in this chapter. A full discussion for all morphological characters is provided; systematic treatment, based on macro-characters such as habit, leaf, floral, fruit, embryo and seed and micro-characters of trichomes. An artificial key applies the most reliable characters for the distinction of the genera.In the systematic treatment 45 taxa are recognized, presenting up-to-date nomenclature, literature citations, type specimens and their locations, synonyms, specimens examined, and distribution maps.Some taxonomic and nomenclature problems in Rorippa, Neslia, Eremobium, Malcolmia, Matthiola, Arabidopsis and Neotorularia are discussed and changes proposed.<strong>Chapter 3</strong> presents macro-morphological characters of the seeds such as seed shape, colour, size, radicle, and micro- morphological characters by (SEM examination) of the epidermal cell shape, anticlinal boundaries, the outer periclinal cell wall and relief of outer cell walls are presented. Three types of basic anticlinal cell wall boundaries are recognized and, six different shapes of the outer periclinal cell wall are described. A key for the identification of the investigated taxa based on seed characters is provided.<strong>Chapter 4</strong> deals with morphological characters of the pollen grains using SEM. In general the pollen morphology varies within a narrow range. The pollen grains are tricolpate. The shape varies from prolate spheroidal, subprolate to prolate. Three pollen types can be distinguished based on the size of lumina. The exine ornamentation of pollen grains varies between genera within tribes and between species within the same genus. The exine ornamentation of pollen was found useful to distinguish between closely related genera.<strong>Chapter 5</strong> deals with the systematics of the tribes of the Brassicaceae, by means of numerical analysis based on sixty-two morphological characters, including vegetative parts, pollen grains and seeds. <strong></strong> Morphological characters have been analyzed using two types of analyses: firstly, we performed a cluster analysis using average taxonomic distance and UPGMA clustering (procedures SIMINT, SAHN, and TREE). Secondly, we performed a principal coordinates analysis (PCO), using the product-moment correlation as a coefficient. The procedures STAND and SIMINT were used to calculate the distance matrix, the procedures EIGEN, PROJ, and MXPLOT to perform the PCO. Four main groups are recognised: Lunarieae, Euclidieae, Matthioleae and a mixed group. Representatives of these groups cluster together based on characters with high factor loading in the PCO analysis. The tribe Euclidieae is the most homogeneous group, and the tribe Arabideae is the most heterogeneous and probably of polyphyletic origin.<strong>Chapter 6</strong> deals with phylogenetic relationships of 83 species belonging to 39 genera of tribes Brassiceae, Alysseae, Arabideae, Euclidieae, Hesperideae, Lepidieae, Lunarieae, Matthioleae and Sisymbrieae. In total 44 species belonging to 28 genera from Egypt were investigated using nucleotide sequences variation of the chloroplast matK gene to assess relationships among genera within tribe and tribes within the family. The topology of Jackknife, parsimony analysis, and Maximum Likelihood trees are largely in agreement. The analysis indicates that tribes Arabideae, Sisymbrieae, Hesperideae, and Lepidieae are polyphyletic