adventice

Adventice is a term used in botany and ecology to describe structures or organisms that arise in an unusual location or from non-native sources. Etymologically derived from the Latin adventicius meaning foreign or arriving, the concept emphasizes origin outside the usual developmental or geographic context.

In plants, adventitious refers to organs that develop from tissues other than the plant’s normal meristems or from non-specialized tissue, often in response to injury, stress, or during vegetative propagation. Common examples are adventitious roots forming on stems, leaves, or cuttings; adventitious buds or shoots arising from non-meristematic tissue; and callus tissue in tissue culture that can regenerate into whole plants. Adventitious growth is frequently exploited in horticulture and propagation techniques, such as rooting cuttings or regenerating plants from callus.

In ecology and agriculture, adventive or adventitious plants are those introduced outside their native range, sometimes becoming weeds. Adventive species may become naturalized if they establish persistent populations, though they can also remain transient or be managed as pests. The term helps distinguish these introductions from native species, even though some adventive plants may eventually integrate into local ecosystems.

See also: adventitious rooting, adventitious bud, adventitious shoot, weed science, introduction and naturalization.