accidental species One of five classes of fidelity used by the Braun-Blanquet school of phytosociology in the description and classification of plant communities. Accidentals are rare species in the community, present either as chance invaders from another community or as relicts from a previous community. Compare exclusive species; indifferent species; preferential species; and selective species.

accidental species One of five classes of fidelity used by the Braun-Blanquet school of phytosociology in the description and classification of plant communities. Accidentals are rare species in the community present either as chance invaders from another community or as relics from a previous community. Compare EXCLUSIVE SPECIES; INDIFFERENT SPECIES; PREFERENTIAL SPECIES; and SELECTIVE SPECIES.