rush (Juncus bufonius) and branched horsetail (E. ramosissimum), while pondweed (Potamogeton spp.) grows in the open water. Although the lake appears rich in phytoplankton, it has not been thoroughly studied. To the south and southwest of the range, between elevation, the wadis support woody species characteristic of the Sahel, such as Egyptian balsam (Balanites aegyptiaca), grey-leaved cordia (Cordia sinensis), red-leaved fig (Ficus ingens), sycamore fig (F. sycomorus), wonderboom (F. salicifolia) and gay acacia (Senegalia laeta syn. Acacia laeta). Chrysopogon plumulosus is the most common grass in the area. Other plants have more Mediterranean characteristics, such as globularia (Globularia alypum) and lavender (Lavandula pubescens) or the more tropical sweet Indian mallow (Abutilon fruticosum) and least snout-bean (Rhynchosia minima syn. Rhynchosia memnonia). The liverwort Plagiochasma rupestre is found around the wadis at these elevations, as are mosses of the genera Fissidens, Gymnostomum and Timmiella. Saharomontane grasslands are found on the slopes, plateaus and the upper portions of the wadis at elevations between . They are dominated by Stipagrostis obtusa and Aristida caerulescens, as well some Eragrostis papposa locally. In addition, shrubs represented by jointed anabis (Anabasis articulata), Fagonia flamandii and Zilla spinosa dot this environment. On the sheltered upper slopes of Emi Koussi is the endemic grass Eragrostis kohorica, named after the volcano's crater. The vegetation above consists of dwarf shrubs, which are generally limited to in height and do not exceed . The shrubbery consists of the species Pentzia monodiana, Artemisia tilhoana and Ephedra tilhoana. At the highest elevations of the Tibesti, tree heath (Erica arborea) grows from moist crevices formed by early lava flows, while 24 different species of moss provide substrate for the tree heath. Various genera of mosses also grow around fumaroles, including Fissidens, Campylopus, Gymnostomum and Trichostomum. Lichens, though rare in the dry climate of the Tibesti, also grow at these elevations, with green rock shield (Xanthoparmelia conspersa), scrambled-egg lichen (Fulgensia fulgens), sunken disk lichen (Aspicilia spp.) and Squamarina crassa found on the highest peaks. Fauna Mammals abound in the Tibesti. Bovids include the endangered addax (Addax nasomaculatus) along with the dorcas gazelle (Gazella dorcas), rhim gazelle (Gazella leptoceros) and a significant population of Barbary sheep (Ammotragus lervia). Rodents are the most represented order of mammals, and include the spiny mouse (Acomys spp.), bushy-tailed jird (Sekeetamys calurus) and the North African gerbil (Dipodillus campestris syn. Gerbillus campestris). Also present are cats such as the African wildcat (Felis