Taxonomic revision of the genus Amaranthus (Amaranthaceae) in Saudi Arabia Author Hassan, Walaa A. Author Al-Shaye, Najla A. 0000-0002-0447-8613 Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, P. O. Box 84428, Riyadh 11671, Saudi Arabia & naaalshaye @ pnu. edu. sa; https: // orcid. org / 0000 - 0002 - 0447 - 8613 naaalshaye@pnu.edu.sa Author Alghamdi, Salma 0000-0001-7716-2233 Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, P. O. Box 84428, Riyadh 11671, Saudi Arabia & saatalghamdi @ pnu. edu. sa; https: // orcid. org / 0000 - 0001 - 7716 - 2233 saatalghamdi@pnu.edu.sa Author Korany, Shereen M. 0000-0002-9355-3952 Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, P. O. Box 84428, Riyadh 11671, Saudi Arabia & smkorany @ pnu. edu. as; https: // orcid. org / 0000 - 0002 - 9355 - 3952 smkorany@pnu.edu.as Author Iamonico, Duilio 0000-0001-5491-7568 Ce. R. S. I. Te. S., University of Rome Sapienza, viale XXIV Maggio 7, 04100 - Latina, Italy & duilio. iamonico @ uniroma 1. it; https: // orcid. org / 0000 - 0001 - 5491 - 7568 & Authors that contributed equally to the work text Phytotaxa 2022 2022-12-20 576 2 135 157 http://dx.doi.org/10.11646/phytotaxa.576.2.1 journal article 53324 10.11646/phytotaxa.576.2.1 1a9bd59f-7293-432f-b3c1-6df0bc659474 1179-3163 7461280 5a. Amaranthus graecizans L. subsp. graecizans Iconography:— Beck (1909 : Tab. 299, figures 1–7, sub A. angustifolius ). Phenology:— Flowering time february. Habitat and elevation:— Human-made habitat (coastal plain), 5–15 m a.s.l. Chromosome number:— 2n = 32 ( Baquar & Olusi 1988 ). Occurrence in Saudi Arabia : — Jizan . Specimina visa selecta ( Fig. 4 ):— SAUDI ARABIA , Jizan , human-made habitat (coastal plain), 5–15 m a.s.l. , 17 February 2021 , leg. Masrhai et Al-shaye (PNUH) , det. Masrhai , conf. Iamonico ( RO !) .