Native plant is a term used to describe plants endemic (indigenous) to a given area in geologic time. This includes plants that have developed, occur naturally, or existed for many years in an area (e.g. trees, flowers, grasses, and other plants). Some native plants have adapted to very limited, unusual environments or very harsh climates or exceptional soil conditions. Although some types of plants for these reasons exist only within a very limited range (endemism), others can live in diverse areas or by adaptation to different surroundings. Research has found that insects depend on native plants. An alternative, but potentially conflicting, usage is to describe plants (and animals) that are indigenous to a geographical area, even if they are known to have self-introduced in historical times, e.g. the Silvereye (Zosterops lateralis) of New Zealand, which was first recorded in the 19th century.