Definição: The U.S. Arid West. One of the 10 regional U.S. Army Corps of Engineers wetland delineation regions for the U.S. and its territories used by the National Wetland Plant List.
Definição: Organic matter in soil which has reached a point of stability, where it will break down no further and might, if conditions do not change, remain essentially as it is for centuries, or millennia.
Definição: Of plant duration, a plant whose life span extends over more than two growing seasons, c.f. annual, biennial, ephemeral, of flowering with respect to architecture, hapaxanthic, monocarpic, pleonanthic