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King Abdulaziz University (2020)

Taxonomic Revision of Some Genera of Aizoaceae in Saudi Arabia

Alotaibi, Modhi Mohammed

Titre : Taxonomic Revision of Some Genera of Aizoaceae in Saudi Arabia

Auteur : Alotaibi, Modhi Mohammed

Université de soutenance : King Abdulaziz University

Grade : Master Thesis 2020

Résumé
Taxonomists are interested in differences and similarities that have taxonomic values among plant species. These characters must be substantial relatively stable and showing differences from individual to individual and from generation to generation. In addition, they choose characters, which are often easy to notice, and expected to be specific treats that has high taxonomic value definite limits among taxonomic categories. Aizoaceae is a leaf succulent family. It is represented by 132 genera, contains approximately 1,900 species, found usually in South African origin. It is represented in Saudi Arabia by 13 genera and 20 species. Most taxa are distributed in the western and central regions and with a few scatterd in the eastern region. In this study, morphological and phenetic species concepts were adapted to study selected genera of Aizoaceae in Saudi Arabia including morphology, anatomy and paylonology. Samples were collected from different locations in the western and southwestern areas in the years 2017 and 2018. Locations include Jeddah, Makkah Al moukrama, Al-Jamoum, Al-Tiff, Allith and Bani malik. Some data were recorded in the field while other data were collected in laboratory. All data obtained were transferred into numerical values to conduct a phenetic approach by using Multi Variant Statistical Package (MVSP). The results showed that five genera in the western and Southwestern of Saudi Arabia represent Aizoacea. Two new recored species were identified for the first time in the flora of Saudi Arabia. Malephora crocea and Mesembryanthum cordifolium are the new records and they have similar characters. Therefore, they were included under sub family Mesembryanthemoidea, while both Sesuvium verrcosum and Zaley pentandra were included under sub family Sesuvioideae given the similarity in the intrinsic qualities. Results from anatomical study showed the presence of secondary growth of anomalous stem and bladder cell, which is characteristic of Aizoaceae. In addition, the presence of different shapes of crystals in stem is also a valued character in the family. As for pollen grains, there was a variation in the pollen shape. For the exine ornamentation : reticureticulate, echinate, granulose. Finally, a synopsis of the taxa is given.

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