3.3. Alternanthera sessilis (L.) DC., Cat. Pl. Horti Monsp.: 77. 1813 ≡ Gomphrena sessilis L., Sp. Pl. 1: 225. 1753. Type (lectotype designated by Mears 1980: 89):—Herb. Hermann 2: 9, no. 116 (BM000621528!, image of the lectotype available at https://data.nhm.ac.uk/object/62000d75-9129-4926-8676-27aad2d9c69a/1691020800000). Alien status:― Neophyte, native to Mexico, Central and South America, Africa, and Asia, according to Clemants (2003), whereas POWO (2023) indicates it as alien in Africa. The native distribution area of Alternanthera sessilis needs further investigations. Concerning Saudi Arabia, we prefer to avoid a definitive state and precautionary consider the species as doubtfully native (as defined in Iamonico 2023). Note that Chaudhary (1998) stated “Recorded from the Southwest. Maybe more widespread”, whereas Alfarhan et al. (2021) indicated the species as invasive (thus not autochthonous). Occurrence in Saudi Arabia:― Al hudud ash Shamaliyah (Osman & El-Ameid Abedin 2019), ʿAsīr (Collenette 1999), Jazan (Miller & Cope 1996, Collenette 1999). Specimina visa selecta:— SAUDI ARABIA. Jazan, Head of dam, Abu Arish, In cornfield, 14 october 1983, Collenette 4655 (E00692536).

Published as part of Hassan, Walaa A., Al-Shaye, Najla A. & Iamonico, Duilio, 2023, A critical inventory of the family Amaranthaceae s. str. in Saudi Arabia, pp. 223-246 in Phytotaxa 626 (4) on page 231, DOI: 10.11646/phytotaxa.626.4.1, http://zenodo.org/record/10212988