Definition: A grassland biome is a terrestrial biome which includes, across its entire spatial extent, an unbroken layer of grasses (Gramineae), sedges (Cyperaceae) or rushes (Juncaceae).
Comment: Preliminary definition. The semantics and definitions of "mediterranean", "subtropical", "tropical", "temperate", "polar", and similar climate types may be transferred to an "environmental condition" class once the semantics of this class have been established.
Definition: Arenosols are sandy soils, including both soils developed in residual sands after in situ weathering of usually quartz-rich sediments or rock, and soils developed in recently deposited sands such as dunes in deserts and beach lands.