Acervular

Acervular is an adjective used in mycology to describe structures or infections that form acervuli, the asexual fruiting bodies that produce conidia in superficial, often massed arrangements on host tissue. An acervulus is typically a cushion- or plate-like aggregation of conidiophores and conidia that develops on or just within the surface of plant material, and from which conidia are shed, frequently via mucilaginous droplets. The acervular form refers to conidiomata or infections exhibiting this acervulate morphology, in contrast to pycnidial (closed, flask-shaped) or sporodochial forms.

Acervular fruiting bodies are commonly associated with plant-pathogenic fungi, including genera such as Alternaria and Colletotrichum, where numerous conidia are produced in the surface masses and dispersed by splash, wind, or contact. The term emphasizes the spatial pattern and reproductive strategy rather than a single genus or species.

Etymology-wise, acervular derives from the Latin acervulus, meaning a small heap or pile, reflecting the clustered appearance of conidia within an acervulus. In descriptive mycology and plant pathology, the label acervular helps differentiate fungi that produce acervuli from those with other conidiomata types, aiding in identification and characterization of fungal morphology and reproductive biology.