Egyptian botanist who was Keeper of the Cairo Herbarium for 25 years and a world expert on Egyptian flora. He was a student of Vivi Täckholm at the University of Cairo and later obtained his PhD from the University of Vienna. On his return to Cairo, he was appointed as an assistant professor in the School of Plant Taxonomy, and became a full professor in 1973. In 1978 he was elected to succeed Vivi Täckholm in the herbarium and as chief editor of Publications of the Cairo University Herbarium (renamed Taekholmia in tribute to its founder). As a botanist, he produced more than 80 papers as sole or first author. His research covered topics in systematics, chemotaxonomy, anatomy, cytology, archaeobotany, ethnobotany, ecology and conservation, with particular reference to the flora of Egypt and Arabia and with a special interest in the Zygophyllaceae of Asia and Africa. He co-authored three books, two with Loutfy Boulos, The Weed Flora of Egypt (1985) and The Street Trees of Egypt (1988). He had recently completed a revised and updated version of Flora Aegyptiaca and was making plans to document the botanical gardens and cultivated plant collections in Egypt. He is commemorated by Anagallis × hadidii Chrtek & Osb.-Kos. His surname was interpreted as 'Hadidi' in the standard form adopted by Brummitt & Powell (1992) but is commonly cited as 'El-Hadidi'.

Sources:
A.I. Aboel-Atta and H.A Loutfy, 2004, "M. Nabil El-Hadidi (1934-2003)", Taxon, 53 (2): 607-609.