Phytotaxa 419 (3): 287–300 https://www.mapress.com/j/pt/ Copyright © 2019 Magnolia Press Article PHYTOTAXA ISSN 1179-3155 (print edition) ISSN 1179-3163 (online edition) Accepted by Marcin Nobis: 10 Sept. 2019; published: 7 Oct. 2019 https://doi.org/10.11646/phytotaxa.419.3.3 287 Cutandia rigescens (Poaceae) a new species to the flora of Iran: distribution, taxonomy and ecology SAMEREH TIRGAN, ALIREZA NAQINEZHAD * & ZEINAB HOSEINZADEH Department of Biology, Faculty of Basic Sciences, University of Mazandaran, 47416–95447, Babolsar, Iran *Corresponding author: a.naqinezhad@umz.ac.ir Abstract During a revision of the genera Cutandia and Catapodium in Iran (Poaceae: subtribe Parapholiinae), the occurrence of Cutandia rigescens was confirmed for the first time on sand dunes along the southern shore of the Caspian Sea in the north- ern part of the country. Twenty-five important morphological and anatomical characters were examined in an attempt to separate this species from Cutandia dichotoma, C. memphitica and Catapodium rigidum, similar taxa already recorded from Iran. In addition to the morphology of the glume, lemma and palea, the most diagnostic characters proved to be: size and shape of long cells in the intercostal zone of leaf epidermis, size of short cells and long cells in the costal zone of the leaf epidermis, size of angular prickles in the leaf epidermis, number and size of vascular bundles in a cross-section of the culm, the presence or absence of parenchymatous cells in the center of the culm and number of florets. Distribution map for Iran, together with vegetation data were presented for all four species. Keywords: anatomy, Caspian Sea, grasses, morphology, Near East, new locality, sand dune Introduction Cutandia Willkomm (1860: 130) and Catapodium Link (1827: 44) and the closely related, Vulpiella (Battandier & Trabut) Burollet (1927: 68), Desmazeria Dumortier (1822: 26) and Scleropoa Grisebach (1846: 431), belong to subtribe Parapholiinae Caro (1982: 41) (tribe: Poeae R. Brown (1814: 582), Poaceae Barnhart (1895: 7)) (Soreng et al. 2015). All are genera of annual grasses typically characterized by (a) a pulvinate habit, (b) little-branched inflorescences, (c) obtuse, rounded or bifid lemmas with awns short or absent, (d) a very short caryopsis, (e) sub-basal hilum and (f) straight-walled long leaf epidermal cells with bulging or angular cross-walls (Stace 1978). The genera Catapodium, Cutandia, Desmazeria and Scleropoa have been the subject of a number of morphologically-based classifications. In the Flora of USSR (Krechetovich & Bobrov 1934), the subtribe Parapholiinae included one species of Cutandia (C. memphitica (Sprengel) Richter (1890: 77)) and three species of Scleropoa, S. rigescens (Trinius) Grossheim (1928: 121), S. rigida (Linnaeus) Grisebach (1844: 431) and S. woronowii Hackel (1912: 15). Subsequently, Tzvelev (1976) transferred Scleropoa rigescens to Cutandia (as C. rigescens (Grossheim) Tzvelev (1957: 27)) and Scleropoa woronowii to the genus Sclerochloa (as S. woronowii (Hackel) Tzvelev (1957: 27)), while Scleropoa rigida remained unchanged. In the Flora Europaea (Stace 1980) Scleropoa rigida became Desmazeria rigida (Linnaeus) Tutin in Clapham et al. (1952: 1434). More recently, S. rigida and D. rigida were reclassified as Catapodium rigidum (Linnaeus) C.E. Hubbard in Dony (1953: 437) (Flora of Turkey; Stace 1985). This brought the classification into line with Flora Iranica (Bor 1970). Flora Iranica also transferred Cutandia rigescens to Catapodium (as C. rigescens (Grossheim) Bor (1970: 52)). However, the record in Flora Iranica for the taxon now accepted as Cutandia rigescens relates not to Iran itself but to the Talish region of Azerbaijan Republic (Bor 1970). Currently, the genus Cutandia in Flora Iranica includes only C. dichotoma (Forsskål) Trabut in Battandier & Trabut (1895: 237) and C. memphitica (Sprengel) Bentham (1881: 118). Extensive fieldwork on the southern Caspian coast of Iran has revealed several sand-dune populations of Cutandia and Catapodium species including some puzzling specimens initially assigned to Catapodium rigidum. On re-examination, these proved to be Cutandia rigescens—a species so far unreported from the territory of Iran. This paper describes Cutandia rigescens, a new species to the Iranian flora. It provides details concerning the identification and distribution of the species and provides an extensive anatomical and morphological comparison with closely related Iranian taxa.