The genus Callitriche (Plantaginaceae, Callitricheae) in Morocco Author Lansdown, Richard V. 0000-0003-0984-4552 Ardeola Environmental Services, 45 The Bridle, Stroud, Gloucestershire, GL 5 4 SQ, UK. & Honorary Research Associate, Royal Botanic Gardens, Kew, Richmond, Surrey, TW 9 3 AE, UK. & r. lansdown @ kew. org; https: // orcid. org / 0000 - 0003 - 0984 - 4552 r.lansdown@kew.org Author Rhazi, Laila 0000-0003-4145-401X Research Centre of Plant and Microbial Biotechnologies, Biodiversity and Environment, Faculty of Sciences, Mohammed V University in Rabat, 4 avenue Ibn Battouta, B. P. 1014 RP, Rabat, Morocco. & laila. rhazi @ um 5. ac. ma; https: // orcid. org / 0000 - 0003 - 4145 - 401 X Author Saber, Er-Riyahi 0000-0001-5442-5280 Faculty of Letters and Human Sciences, Department of Geography, Moulay Ismail University, BP 11202 Zitoune, Meknes, Morocco. & erriyahisaber @ yahoo. fr; https: // orcid. org / 0000 - 0001 - 5442 - 5280 erriyahisaber@yahoo.fr Author Madihi, Mohammed El 0000-0002-2425-5396 Research Centre of Plant and Microbial Biotechnologies, Biodiversity and Environment, Faculty of Sciences, Mohammed V University in Rabat, 4 avenue Ibn Battouta, B. P. 1014 RP, Rabat, Morocco. & Tour du Valat, Research Institute for the conservation of Mediterranean wetlands, Le Sambuc, 13200, Arles, France. & elmadihi. med @ gmail. com; https: // orcid. org / 0000 - 0002 - 2425 - 5396 elmadihi.med@gmail.com Author Grillas, Patrick 0000-0002-7448-148X Tour du Valat, Research Institute for the conservation of Mediterranean wetlands, Le Sambuc, 13200, Arles, France. & grillas @ tourduvalat. org; https: // orcid. org / 0000 - 0002 - 7448 - 148 X grillas@tourduvalat.org text Phytotaxa 2022 2022-07-19 555 1 53 72 http://dx.doi.org/10.11646/phytotaxa.555.1.4 journal article 102837 10.11646/phytotaxa.555.1.4 dde6df02-b3ce-471c-9e70-0b28507dc49e 1179-3163 6875713 4. Callitriche lusitanica Schotsman (1961: 112) Type : —Castelo Branco, rib. Ponsul, VI-1881 . A.R. da Cunha s.n. ( LISU ) . Distribution: — Callitriche lusitanica is endemic to the Mediterranean Basin, but its distribution is poorly known. It is widespread and abundant in the centre and west of the Iberian Peninsula and occurs in North Africa in Morocco , Algeria , and Tunisia , as well as from the islands of Sardinia and Sicily east to Israel ( Lansdown et al . 2017 , Prančl et al . 2020 ). In Morocco it appears to be restricted to the coastal lowlands from Safi north to Tangiers, where it is not uncommon south of Rabat ( Fig. 1D ). Habitat and ecology: —Throughout much of its range, C. lusitanica occurs in gravel- or cobble-bed rivers on siliceous soils, where it may form large stands in the main channel and backwaters ( Lansdown et al . 2017 ). In Morocco although it has been recorded from slow-flowing water ( Fennane et al . 2007 ), it is more frequent in seasonal waterbodies. Notes: —The Iberian Peninsula and Morocco appear to represent the core distribution area of this species, however scattered records from the larger Mediterranean islands, other countries in North Africa, and from Israel suggest that it may have a similar distribution to that of C. brutia subsp. naftolskyi . It is clearly under-recorded throughout much of its range and since it is poorly represented in herbaria, it is difficult to define its distribution. Recognition: — Callitriche lusitanica can be distinguished from all other Callitriche species recorded from Morocco by the combination of the translucent leaves that are not connate at the base, and the broadly-winged fruit that are blackish when mature. Illustrations: —Figures in Lansdown [2008: 24 (5-5x), 75, 77]; Plates in Lansdown et al . (2017: 96–97) . Specimens examined: — MOROCCO : Prope Oppidium Boulhaut , in aquis stagnantibus, s.d. , R. Maire 21-4 ( RAB 9663 ) . A Casablanca , daya du camp d’Aviation , 27 April 1922 , R. Maire s.n. ( RAB 9648 ) . Region Rabat / Zaire , daya El-Hrcha , près de Souk el-Arba des Sehoul , 2 March 1970 (localite precise 4 June 1975 ), Mathez , Andreas , Schotsman 6 ( RAB 44623) . Avec C. regis-jubae , Reg Rabat , 4 km SE de Tiflet (localité précise 4 June 1975 ) 2 March 1970 , Schotsman 7 ( RAB 44650) . Plateau centrale, Mont NW Vasques de l’Ighzan Ain Boad pers Si Otsmane , s.d. , J. Mathez 7313 ( RAB 47215) .