Namibian Saltmarsh
In the more saline zones where flooding rarely occurs Sporobolus virginicus and Scirpus dioicus are the main halopytes (salt tolerant species) while in less saline areas Odyssea paucinervis predominates. In areas regularly flooded at high tides the succulent Arthrocnemum affine is one of the main pioneer species. Other plants found in the saline soils of the littoral zone include Aizoanthemum mossamedensa, Chlois pubescens, Leucophrys mesocoma, Paspalm vaginatum, Salsola zeyheri, Sesuvium mesembryanthemoides, Sesuvium sesuvioides and Suaeda fruticosa. In the more gravelly patches, the endemic Arthraerua leubnitziae (Amaranthaceae) occurs together with Zygophyllum stapffii.
Namibian Pans
These include species-poor clay pans in which Platycarpha carlinoides is one of the main species and slightly richer loamy pans dominated by Aristida adscensionis. Associated species with both of these pan types include various annuals such as Hydrodea bossiana and Pentzia heteroensis.
Namibian Sand Dunes
In large parts of the Namib, especially in the south, there are large shifting dunes up to 300 m high and largely devoid of vegetation. The main species able to tolerate these conditions are Eragrostis cyperoides, Stipagrostis sabulicola and the endemic Stipagrostis gonatostachys (Poaceae). On smaller dunes endemics such as the strange spiny shrub Acanthosicyos horrida (Cucurbitaceae) and the endemic Trianthema heteroensis may be present together with Psilocaulon marlothii. In the slightly wetter areas Limeum fenestratum and Stipagrostis lutesens become the more important species. On the more compact substrates Galenia africana, Pterodiscus aurantiacus, Sesuvium portulacastrum, Vogelia africana, Zygophyllum orbiculatum, Z. simplex, the endemic Stipagrostis subacaulis (Poaceae)and occasionally the near endemic Welwitschia mirabilis (Welwitschiaceae) are some of the species encountered.
Namibian Sandy Plains
These have been divided into several communities depending on the amount of moisture available. In the moist foggy zone the endemic Arthraerua leubnitziae (Amaranthaceae) is one of the dominant species and is particularly conspicuous on gypsum plains, while in the dryer areas Salsola tuberculata and Stipagrostis ciliata or S. obtusa predominate. Two of the more spectacular formations associated with this habitat are the Welwitschia and Teloschistes plains. In certain areas, such as in the vicinity of the Swakop River, the bizarre near endemic gymnosperm Welwitschia mirabilis (Welwitschiaceae)completely dominates the vegetation. It tends to follows underground watercourses. Equally bizarre is the orange fructicose or shrubby lichen Teloschistes flavicans, which together with other lichens such as Parmelia convoluta and various species of Usnea, dominated some of the coastal plains.
Namibian Washes
With increasing amounts of water from rainfall, runoff or ground water, a gradation of different communities can be found. Some of the dominant species along this gradient include Acacia reficiens, Asclepias buchenaviana, Petalidium setosum and the endemic Adenolobus pechuelli (Fabaceae). At the wetter end of the spectrum, such as pioneer river communities, there are Argemone ochrleuca, Datura innoxia and D. stramonium and finally ‘fully fledged’ river communities with Acacia erioloba and A. albida.
Namibian Rock Outcrops
In the coastal fog zones, Salsola tuberculata and Zygophyllum staffii are the main rocky outcrop species. Moving inland their dominance is replaced by Sesuvium sesuvioides and Stigagrostis obtusa in the dry areas, but with increasing rainfall or run-off Anthephora pubescens, Commiphora glaucescens, Monechma genistifolium and Petalidium variabile predominate. In addition to the above, rocky outcrops provide habitat for various succulents such as Lithops rushiorum, Othonna lasiocarpa and the endemic Sarcocaulon mossamedense (Geraniaceae), dwarf shrubs such as Drosanthemum luederitzii, Rushia sedoides and Tetragonia arbusculoides, as well as annual grasses such as the endemic Stipagrostis namibensis and S. subacaulis (Poaceae). However, the annuals only become conspicuous after good rainstorms.
Further information required.
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