Cyperus iria

Raab-Straube, Eckhard von & Raus, Thomas, 2025, Euro + Med-Checklist Notulae, 18, Willdenowia 55 (1), pp. 107-144 : 122

Cyperus iria L. – Fig. 11B.

N Gg: Georgia: Autonomous Republic of Adjara, Batumi, Gonio, Apsaros 1 st dead end, 41.57866°N, 41.57246°E, wasteland in private garden, on excavated wet red-earth soil, 17 Sep 2023, Vishnyakov (BR, IBIW 76355, LE; photo: https://www.inaturalist.org/observations/183833695); ibid., 41.57867°N, 41.57102°E, edges of unpaved road to seacoast, wet depression, in puddles, 17 Sep 2023, Vishnyakov (BR, IBIW 76354, LE; photos: https://www.inaturalist.org/observations/183832749); ibid., Adjara, Kobuleti municipality, Kobuleti, wasteland near cemetery, 41.87708°N, 41.78332°E, disturbed wet habitat, 19 Sep 2023, Vishnyakov (IBIW 76362). – This is an annual weed from the Old World tropics and subtropics; it is introduced and widely naturalized in the New World ( Tucker & al. 2002). In the Euro+Med area, it was reported so far only as naturalized from Italy ( Jiménez-MejÍas & Luceño 2011 +). However, claims from Italy are erroneous and referable to C. microiria Steud. ( Fig. 11C), another noxious Asian weed, as already pointed out by Raynal (1977; see also Verloove 2014; Verloove & al. 2014; Galasso & al. 2018). These two species, and to a lesser extent C. amuricus Maxim. , are often confused. In C. microiria , the glumes are more widely spaced (successive glumes 1.1– 1.5 mm apart vs 0.7–0.9 mm in C. iria ) and bear a more prominent mucro (0.2–0.25 mm long vs 0.05–0.12 mm in C. iria ) ( Raynal 1977; Tucker & al. 2002; Fig. 11C). In the autumn of 2023, C. iria was found on the Black Sea coast in Gonio S of Batumi, W Georgia (Autonomous Republic of Adjara). The species appears to be naturalized under wet, subtropical conditions and was collected from three localities in two municipalities (Batumi and Kobuleti). It is locally abundant in disturbed habitats and apparently well-established. In the very same area and in identical habitats, C. microiria is also found. The latter species was also not known from Georgia, but after herbarium studies it turned out to have occurred there since the 1980s ( Vishnyakov 2024). Both species are probably often confused in this region and their populations should therefore be studied carefully. To our knowledge, C. iria was reliably recorded in the Euro+Med area so far only from Spain, where it was inadvertently introduced with coconut fibre from tropical Asia ( Verloove & al. 2014). However, this record referred to an ephemeral occurrence in a nursery (E. Laguna Lumbreras, pers. comm. Feb 2024). The records presented here apparently relate to the first naturalized populations of C. iria in the Euro+Med area. This species is among the most important cyperaceous weeds in terms of its adverse effect on agriculture. It is ranked the 33 rd world’s worst weed and is a major agricultural pest, particularly of rice ( Holm & al. 1977).

F. Verloove & V. S. Vishnyakov