Emergent macrophytes are frequently much reduced in the Maghrebian region by overexploitation of water resources but many are still abundant in the Egyptian Delta lakes and in Moroccan mountain lakes. Emergent plants include Juncus acutus, J. maritimus, J. rigidus, Scirpus spp., Typha angustifolia, and Phrag-mites australis, and are so abundant in the Nile delta lakes that they not only provide sheltered habitats for many reed nest birds but also permit harvesting for a variety of domestic uses. In the predominantly fresh water lakes, submerged vegetation in many SMR lakes is commonly composed of abundant charophytes, Tolypella glomerata, Nitella opaca, N. gracilis, N. hyalina, N. translucens, Lamprothamnium papu-losum, L. succinctum, Chara hispida, C. vulgaris, C. aspera, and C. canescens. Other occasionally common aquatic macrophytes, especially in the more brackish sites, are Naias minor, N. major, Ruppia cir-rhosa, R. maritima, Potamogeton, Myriophyllum, and Ceratophyllum. Isoetes velata and I. lacustris are mainly common in freshwater (dayas types 3 and 4).
Floating aquatic plants such as the water ferns (Lemna gibba, L. minor, and Azolla filiculo'ides), water lettuce (Pistia stratoites), and the water hyacinth (Eichhornia crassipes) can form nuisance growths on surface waters and the latter two species are restricted to Egypt.
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