Callitriche obtusangula

Distribution: — Callitriche obtusangula is known from Europe and North Africa. It occurs from the UK and the Netherlands to Austria and Greece in the east, as well as in Morocco, Algeria, and Tunisia. It is at the southern limit of its range in Morocco, where it has been recorded from three sites in the north and on the Central Plateau (Fig. 4 A). Habitat and ecology: — Throughout most of its range, Callitriche obtusangula typically occurs in permanent waterbodies such as rivers, fen drains, ditches, and pools in freshwater systems, extending into the upper margins of brackish coastal wetlands. In Morocco it has been recorded from a stream, a reservoir, and low-lying wet grassland. At one site in a stream near Oulmès, it was recorded with a range of species of which 39 % can be considered truly aquatic, 48 % marginal, and 13 % terrestrial, reflecting the perennial nature of the stream. Other species recorded were similar to those with which it occurs in Europe, including Callitriche stagnalis, Ceratophyllum demersum von Linné (1753: 992), Helosciadium nodiflorum (von Linné 1753: 251) Koch (1824: 126), Lemna gibba, Lythrum portula, Nasturtium officinale, Potamogeton nodosus Poiret (1816: 535), Scrophularia auriculata von Linné (1753: 620), and Veronica catenata. It is a lowland species in the north of its range (Lansdown 2007), but has been recorded up to 1200 m in Sicily. Elevation in Morocco: 0 — 1100 m. Recognition: — Callitriche obtusangula can be distinguished from all other Callitriche species recorded from Morocco by the combination of large, unwinged fruit with parallel mericarps, and large anthers with yellow pollen. Illustrations: — Figures in Lansdown [2008: 25 (9 - 9 x), 97, 99]. Specimens examined: — MOROCCO: Barrage Smir, Tetouan. M’diq, 4 April 1994, J. M. Montserrat, B. Vales s. n. (RNG). Low-lying, heavily grazed area by lake, very wet in parts, 4 km from Moulay Bousselham on road E to Kenitra (83 km), Kenitra Province, 13 m, 25 May 2002, S. L. Jury, M. Ait Lafikh, R. Brown, M. A. Carine and F. J. Rumsey 19284 (RAB 65427, RNG 27142). River near Oulmès, 30 April 2019, R. V. Lansdown, L. Rhazi, P. Grillas, M. El Madihi, J. Snoeks s. n. (RAB).