adventif

Adventif is a term used in French that corresponds to the English adjective adventitious. It denotes something that arises from an outside or non-native source, or that appears in an unusual place or position. In English-language scientific writing, adventitious is the more common form, while adventif appears primarily in French-language texts or comparative usage.

In botany and plant science, adventitious describes tissues, organs, or organisms that develop away from their usual origin. Adventitious roots, for example, grow from non-root tissues such as stems or leaves—often in response to injury, wounding, or during propagation by cuttings. Adventitious buds may form on stems, leaves, or other non-typical sites. This property is exploited in horticulture to propagate plants from cuttings or to repair damaged tissues.

In ecology and biogeography, adventive or adventitious species are those introduced from outside the native range. They may appear in a region due to human activity or natural dispersal. Adventive species are not native and may or may not establish self-sustaining populations; if they do, they may become naturalized, and in some cases invasive, depending on their ecological impact.

In other biological contexts, adventive can describe features or processes that occur in unusual places or origins, such as adventitious tissue development in anatomy. The term emphasizes an origin or occurrence that is outside the standard or native context, distinguishing it from true, intrinsic formation.