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 5c. Amaranthus graecizans L. subsp. thellungianus (Nevski) Gusev, Bot. Zhurn. ( Moscow & Leningrad ) 57(5): 462. 1972 Amaranthus thellungianus Nevski, Trudy Bot. Inst. Akad. Nauk S.S.S.R., Ser. 1, Fl. Sist. Vyssh. Rast. 4: 311. 1937 Holotype :— TURKMENISTAN , In angustiis Bulak-Dara ad pedem montium Kuhitang supra pagum Karluk , 11 August 1931 , Nevski 730 [LE non vidi fide Townsend (1985) ; photo of the isotype at K000814926!, image of the photo of the isotype available at http://apps. kew.org/herbcat/getImage.do?imageBarcode=K000814926). Chromosome number: —Not still counted. Occurrence in Saudi Arabia :— Chaudhary (1998: 238) indicated this taxon as “probably doubtful” in Saudi Arabia. No finding was done during the filed surveys. Further researches are necessary to verify the occurrence of this taxon in the country.