Inluded here are the Caroline Islands, Mariana Islands, Marshall Islands, Gilbert Islands, Ellice Islands, Phoenix Islands, Tokelau Islands, Baker Island, Banaba Island, Howland Island, Nauru Island and Wake Island.

The upland volcanic parts of many of the higher islands support grasslands of varying extent. These are generally referred to as savannas although they are normally not flat and trees may be absent. On Guam the dominant grasses include the endemic Dimeria chloridiformis (Poaceae), a tufted, soft bluish-green grass that occurs on the more level or gently sloping areas, or on the steeper slopes and ridges, Miscanthus floridulus, a coarse, sharp edged, cane like-grass that can reach heights of 3 m. The few trees may include Casuarina equisetifolia or the endemic Xylosma nelsonii (Flacourtiaceae).  Other associated endemic species include the shrubs Alyxia torresiana (Apocynaceae), Melastoma marianum (Melastomataceae), Myrtella bennigseniana (Myrtaceae), Pandanus fragrans forma savannarum (Pandanaceae), Timonius nitidus (Rubiaceae) and the herbaceous species Hedyotis megalantha (Rubiaceae). However, many of the characteristic savanna plants are pioneer species that rapidly colonize any denuded areas. The deeply weathered volcanic rocks on Guam often undergoes extensive erosion leaving bare scars for colonization by these species, while the more mature areas may be composed of almost monospecific grasslands. 


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